Can I create a form with an e-signature that is saved in Salesforce

A bit about forms requiring a signature
Many forms require the form fillers to give their consent using a signature. Not every form builder provides an electronic signature field, and so in some cases this forces you to do some manual work in order to tie loose ends. Sometimes the form has to be printed, signed and sent back via fax, in other cases fillers need to scan their signature and upload it to the form, or send it to you via email. 
A bit about forms requiring a signature
Many forms require the form fillers to give their consent using a signature. Not every form builder provides a electronic signature field, and so in some cases this forces you to do some manual work in order to tie loose ends. Sometimes the form has to be printed, signed and sent back via fax, in other cases fillers need to scan their signature and upload it to the form, or send it to you via email. 
This just adds to your work load, forcing you to manually update your records in Salesforce. and we all know this kind of manual work is not only time consuming but it can also lead to mistakes, & data getting mis-filed or lost.

So...is it possible to add a electronic signature to my form and have all the data entered stored in Salesforce?
In one word : Absolutely.

How does this work exactly?
Adding a signature element to your form is simple - all you have to do is drag it from the "Elements" panel.
This field enables the filler to e-sign inside of it using his mouse (or finger, for touch screens like in mobile).
Read more about the signature element

What about storing the entered data - including the signature - in Salesforce?
FormTitan provides a very powerful integrating with Salesforce. One that allows you to "Push" the data entered in your form to as many SF objects as you need, and in real-time too. In order to push the signature and the rest of the data all you need to do is:
1- Create a "PDF Mapping" in your form, Which will generate a PDF based on the entered data (including the signature of course) 
2- Configure a "Push" integration to Salesforce, in which you map all the fields in your form to the fields of the relevant SF object/s.  and as for the Pdf Mapping - simply map it to Salesforce as attachment, File or document. 
Read more about setting up the PDF mapping and mapping it to Salesforce
Read about the Push integration to Salesforce