I want to pass variables such as name, email, and phone numbers to the forms

i want to pass variables such as name, email, and phone numbers to the forms, so my customers dont have to write their names (when they're signed in). 

It is possible to prepopulate fields here in JotForm. Please use the Field Prepopulator App in order to pre-register values to some fields. 

You may also refer to this guide: https://www.jotform.com/help/71-Prepopulating-Fields-to-Your-JotForm-via-URL-Parameters.

If you have any questions, let us know. Thank you.