Auto fill field based on cliend id

[laks]

I have a 2 tables Events and clients

I have a form based on events table that clients submit their event requests

i want to when they open the form to have an id field based on clients table  that once they type (or choose from a drop down list) All their  info is added to the form so they dont have to type first name , last name , email and phone

[Aj_Tavez]

Following. Need to learn how to do this also:

ORDER Table.

CLIENT Table.

A form on my website from the ORDER table asks for all information from the client, including their email address. I need for the NAME, PHONE, EMAIL, and SUBSCRIPTION fields in CLIENT table to auto-populate in the ORDER table. Then I have a zap configured that will automatically send an email and text message to the client confirming our receipt of their order request, which is pretty much what I see you trying to accomplish. Would be very appreciative of anyone's help in achieving this!