If I want to send an email to contacts asking them to update their birthday and their address there is currently NO WAY TO DO THAT without requiring that they also view and submit any fields that you have made mandatory. You know some mandatory fields are not intended to be seen, much less updated, by our Contacts. Also, and for whatever reason, Zoho CRM does not allow us to pass Contact ID as a field/value to Zoho Forms, Zoho Surveys, or the Contact Portal. That means there is no way to prompt any record in Zoho to update only a portion of their record themselves without exposing mandatory fields. 

This functionality is not new, its been around in CRMs for 20 years. Not only that, but to allow customers to incrementally update predefined parts of their record themselves is a requirement for "Progressive Profiling" (see  https://www.kunocreative.com/blog/progressive-profiling)

Please find a way to

1) pass the Zoho record ID

2) remove the requirement to expose and update required fields as the only field required is the ID

3) make the process of allowing Contacts and Leads etc to update themselves simpler. It need to be able to be done by landing page (survey or form), and by popup layer on a webpage