form auto fill from in an email

I’m seeing that when I’m in an email (e.g., Yahoo), and click a link in the opened email that takes me to a form, the auto fill choice that comes up for an email isn’t the contact I set in Safari but apparently the first contact in my contacts, and I’m unable to scroll to other email addresses to pick. Do email apps use the Safari interface to open web forms, or do they use their own interface? Is there any way to change anything so my preferred email addresses show up? I suppose I can try to create a new contact that always comes first in my contacts and has my preferred form fill email addresses and see if that works.