PHP website forms to push data to Zoho CRM

We have a PHP website, and require data to be pushed from the website contact forms to Zoho CRM. The contact forms are not Zoho Forms, so this will need to be done via the REST API method.

Please note that this project is for programming on the website end only, as we have a Zoho partner dealing with the Zoho CRM end. The number of forms and fields this is required for are:

Form 1:
- 1 x email field
- 1 x tickbox field

Form 2:
- 1 x email field

Form 3 (on 5 different pages - so each one will have it's own tag):
- 3 x text fields
- 1 x email field
- 1 x telephone field
- 1 x postcode field