Form to update a CRM contact field

Form to update a CRM contact field

Hello I need an help as I am going crazy.
I need to create a form where there is a dropdown field with the contacts of Zoho crm (if possible filtered on the base of a field) and where other fields will be be automatically fetched with zoho crm data as the user of the form could update email or phone.
Which could be the best solution forms or creator?
with forms I am able to do everything but I can't find the solution to insert a dropdown field but only a field where the user can insert two digits and then the contact name is suggested.
In creator the block is how to update the fields in crm
I hope somone could suggest me how to move
regards
paolo