How do I add an electronic signature to our forms?

how do i add an electronic signbure

To add signature and any other widgets to your form, you should check out this guide: How to Add a Widget to your Form

Now in regards to capturing signatures on your form there are several alternatives:

E-Signature

Smooth Signature

Adobe DC eSign Services

SigPlus

DocuSign

My suggestion would be E-Signature if you are looking for a simple way to capture a signature or Adobe DC eSign Services if you have an account with Adobe that you can use to sign the documents over Adobe.