Currently, our builder doesn't offer a feature that would let you add a signature automatically to the created file (resume or cover letter).
But no worries! There's still a solution to this case.
You can simply print your document, sign it by hand and then scan it and save it as a PDF file.
If you have access to some PDF editor software, you can also add the signature using that program.
Either way, your document will look professional and will surely meet the requirements.