How does the Signature on a form work? How do people sign digitally, without having to print out a form?

How does the Signature on a form work?  How do people sign digitally, without having to print out a form?

It depends on the device. If you're using a computer device, you can use the mouse for signature. If you're using a mobile device like a phone or tablet, you can use your finger or pen tablet for signature. 

Please check these useful links:

https://www.jotform.com/help/433-How-to-Add-an-E-Signature-to-Your-Form

https://www.jotform.com/guide-to-electronic-signatures/

https://www.jotform.com/blog/e-signatures/

I hope this information helps.

Just to add, when the user submitted the signature to your form you can view them in the Submission Page. 

Here's a guide: https://www.jotform.com/help/269-How-to-View-Form-Submissions