The best method for passing data generated from other app forms into a new app form that is launched from a contact’s profile page on the “People” tab is via the contact-summary context.
A good realistic example of using a contact summary is the one for pregnancy in the default config. Among other things, that contact-summary config sets the pregnancy_uuid value in the contact-summary context when a new pregnancy report is submitted for the contact. Subsequent forms for that patient can then reference the pregnancy data for the patient using that pregnancy_uuid value (e.g. the pregnancy_danger_sign_follow_up form).