Any way to submit information to be attached to a Contact?

Any way to submit information to be attached to a Contact?

Is there any way for an external system to submit information to be added to a Contact in Zoho CRM?

My preference (I think) would be to add a line or two of information to the Description field of an existing Contact.

A second option would be to add a Note, Event, or Task to an existing Contact.

E-mail address would be the preferred key to select the proper Contact.