Best e-signature application software

[Alexa Potocki]

I'm looking to build my own application for tenant screening. Ideally, this would be a simple Word document that either is sent out as is or is converted into a PDF or something similar. The main thing is I need it to be signable electronically. 

What is everyone using these days? Is there free software that makes it easy to create and send to applicants so they can complete, design, and return all without printing and ideally on their phones? (I am familiar with Zillow, but there are additional questions I like to ask that it does not include.)

Thanks in advance for your input.

Alexa