When signing an accessible document, note the following:
The Signer Experience of an accessible transaction supports content magnification via the web browser (up to 200% zoom).
The Signer Experience of an accessible transaction supports the navigation of fields via the keyboard's TAB key.
Signers of an accessible HTML document use both the keyboard and mouse. Accessible HTML provides them with audio notifications via a screen reader.
Some known limitations for signers are described here.