Signature field

The Signature field captures a hand-drawn signature on a canvas. The user signs with a finger on a touch device, stylus, or mouse. On save, the signature is encoded as a PNG and either uploaded to the item's SharePoint Image column or attached to the item via the List Attachments endpoint.

Because the upload is a follow-up write, the Signature field uses the

save flow's post-save writer mechanism, the SharePoint item is created first, then the signature is attached.

Common properties

Type-specific properties

Saved digital signatures

A workspace can keep a library of reusable signature images. When it has at least one, every Signature panel in that workspace shows a Use saved signature dropdown under the canvas. Choosing an entry stamps that image onto the canvas, scaled to fit and centred, so the person filling in the form does not have to draw anything. From that point on the field behaves exactly as if it had been signed by hand: the same value reaches the hidden input, the same required check applies, and the same upload runs on submit.

Managing the library. A workspace admin uploads and names signatures in the SaaS dashboard under Settings, Branding, Digital signatures. PNG, JPEG, GIF, and WebP are accepted, up to about 190 KB each, with a limit of 50 per workspace. The images are stored in the Forms 365 database rather than in SharePoint, so they resolve from any site in the tenant without running into per-site permissions.

Shared and personal signatures. There are two kinds, and the dropdown shows both:

• Shared signatures are uploaded by an admin under Settings, Branding, Digital signatures. Everyone in the workspace sees them. Use these for company marks and approval stamps.
• Personal signatures are saved by someone while filling in a form. They appear only for the person who saved them, never in anybody else's dropdown.

Because of that, the dropdown is different for different people. Someone with no personal signatures, in a workspace with no shared ones, sees no dropdown at all.

Saving one while filling in a form. Under the canvas there is an Options button next to Clear. It opens a menu with Create Signature for re-use, which opens a small dialog where the person can draw a signature (or upload an image), give it a name, and save it, without waiting for an admin. Whatever they have already drawn on the form is carried into the dialog, so signing once and saving it takes a couple of clicks. Once saved it appears in their dropdown immediately, and stays private to them.

Editing what you saved. The same Options menu has Edit saved signatures, which lists the signatures you saved and lets you rename one, replace its mark by drawing or uploading a new image, or delete it. Deleting asks for a second click first. Renaming or replacing does not affect forms that were already signed: those carry their own copy of the image, not a link to the library.

Private or public. Each of your signatures shows a Private or Public badge, with a button to switch it. Private means only you see it in the dropdown. Public means everyone in your organisation can see it and apply it to any form, which is what you want for a company or role stamp. Publishing asks you to confirm first, because it is a real widening of access: once a signature is public, a colleague can sign with it. Making it private again is immediate and needs no confirmation, though it does not undo anything already signed.

You can only change signatures you saved or published yourself. Anything published by an admin, or by somebody else, is listed read-only. That is enforced on the server, not just hidden in the dialog. Admins curate the workspace library under Settings, Branding, Digital signatures.

An admin can switch all of this off under Settings, Branding, Digital signatures if they would rather curate the library themselves. When it is off, the Options button does not appear at all, and the library becomes read-only for people filling in forms. Every entry records who added it, and admins see every signature, personal ones included, so they can tidy up.

Where it lands on the canvas. A picked signature is centred by default. Use Saved signature position in the designer to place it Left, Centre or Right instead, which is useful when the canvas is wide and the mark should line up with something printed beside it. It is scaled to fit and never stretched, so a signature wider than the canvas fills it and all three positions look the same. This only affects picked signatures and ones reloaded from a saved form: a signature drawn by hand stays where the person drew it.

Turning it off for a field. Clear the Allow saved signatures checkbox in the designer. The dropdown and the save link then never appear on that field, even when the library is populated. Use this for forms that must carry a genuinely hand-drawn mark.

Digital stamp

Also referred to as the signed-by caption; the two names mean the same feature.

Tick Digital stamp in the designer and the field stamps a line under the signature as soon as it is signed:

Digitally Signed by: Megan Bianchi - Date: 2026.07.29 08:27:19 +10:00

The name comes from the signed-in SharePoint user. The time comes from the Forms 365 server, not from the clock on the signer's PC, because a timestamp that the signer can set by opening Date and Time settings is not worth recording.

It records the signer, not the reader. Both values are captured at the moment of signing and then frozen into the saved image. This is the one place in Forms 365 where placeholders do not re-resolve on every load, and that is deliberate: a stamp that re-resolved would name whoever opened the form next. Open a signed form a month later, as somebody else, and it still says Megan Bianchi.

It travels with the signature. Because the stamp is part of the image rather than a separate field, it shows up anywhere the signature does: the display form, the thumbnail in a SharePoint list view, and any PDF report generated from the item. There are no extra columns to create.

It sits under the signature, not under the panel. The stamp is placed below the lowest point of the ink with a small fixed gap, so it never covers the mark: sign near the top of the box and the stamp rides up to just under it, sign down to the bottom edge and it drops into the space reserved beneath.

It tracks the mark sideways too. The text starts at the left edge of the ink and wraps to the ink's width, so a signature in the middle of the panel gets its stamp underneath it rather than stranded at the far left. Two limits keep that sensible:

• A minimum width, so a small mark such as a dot or a single initial still gets a readable text column instead of one a few pixels wide.
• A right-hand limit, so a mark in the far corner slides its stamp back inside the image rather than running off the edge. In that case it ends up flush right, across up to three lines.

Stamps wrap to at most three lines and then truncate with an ellipsis.

Re-signing starts clean. When this option is on, drawing on a signature that was already saved clears it first and stamps a fresh one, rather than adding strokes to somebody else's mark.

Changing the wording

Ticking the box fills Digital stamp text in with the standard wording, so you do not have to set anything to get the line above. Edit it in place if you want different wording, or clear it and the default applies anyway:

Approved by [Me:Title] ([Me:Email]) on [Now:dd/MM/yyyy] at [Now:HH:mm Z]
Signed for {CompanyName} by [Me:Title], [Now:dd MMMM yyyy]

[Me:...], [Now:...] and {FieldName} all work. For the date part, ZZ renders the UTC offset (+10:00) and Z renders the zone name (AEST); both are worth including, because a bare time with no zone is ambiguous the moment somebody reads it from another country. The full list of date patterns is in the placeholders reference.

If the template mentions [Me...] and SharePoint cannot tell us who the user is, no stamp is applied at all. A line reading "Digitally Signed by:" with nothing after it would claim less than saying nothing.

JavaScript recipes

const signed = !!f365.field('CustomerSignature').value;
//   value is the data URL while in the form; cleared after upload completes.

f365.field('CustomerSignature').clear();

f365.events.onBeforeSave(() => {
  if (!f365.field('CustomerSignature').value) {
    f365.ui.showAlert('Customer signature is required to submit.');
    return { cancel: true };
  }
  f365.field('SignedByName').value = f365.user.current().displayName;
  f365.field('SignedOn').value = new Date().toISOString();
});

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