Yoti eSignatures supports PDF and Microsoft Word (Office 97 and later). Your documents cannot be password protected and must be smaller in size than 15MB.
If you upload a Microsoft Word document, Yoti eSignatures converts it to PDF before sending it out for signing. If you wish to know more about this, click here.
Note that if your Word document contains hyperlinks, you should convert it to PDF first before upload (following the Microsoft guidelines here), otherwise the links will not work when it is signed.