How to design a form?

looking for a form for my gyms that I can add working and they select yes or no or put their initials and then they sign with their finger at bottom.. does that exist? 

Here are a few templates that you can use as gym registration forms:

https://www.jotform.com/form-templates/grace-transformation-challenge-application

https://www.jotform.com/form-templates/gym-membership

Here is a guide on how to use templates as form: How-to-Use-Form-Templates

For taking a signature you can add a widget at the bottom of the form. Reference Guide: How-to-Add-an-E-Signature-to-Your-Form

Feel free to reach us in case you need any further help from our end.