Allow users to sign a form created in K2

I would start by questioning the requirement.  Do you really need this, or is it just a carry over from the way things used to be done on paper?  Typically you only need a signature for legal documents and financial documents.  Those will stand up in a court as a legal acknowledgement as they can absolutely be traced to the person who signed and what they saw at the time of signing.  That is the purpose of digital signature tools like DocuSign:  to replace pen and paper with a digital but legally binding signature.  

Not everything is a legal record.  Do you expect legal action over an attendance sheet?  Is it a legally binding contract?  Sometimes you just need an e-signature.  That's simply a record of who filled it out.  It is for tracability rather than legal purposes.  For this all you need to do is record the logged-in identity of the user who filled it out. That's pretty easy to capture in the data.  Even better, if the attendance sheet is a step in a workflow, the system automatically records the useridentity of the person who completed the step and that is available in the OOTB K2 reporting.

Thanks for your suggestion. I was also initially thinking of just recording of logged in identity of user but there are scenarios where employees who will be signing the sheet would not have any log in details. Long story on why this is but in short, final business decision for now was we do not require all employees to be logging in. 

I managed to get in touch with someone from K2 and was advised to try out the Digital signature like what @boringNerd suggeste as well. With the same caveat though that this is something developed out of K2.

thanks again...

thanks. I managed to set this up and satisfies what we exactly need for now.