How to sort contacts by first or last name on iPhone
iOS likes to arrange your contacts list by the first letter of their last name, that’s what. No biggie, we can very quickly change that.
Go to Settings → Contacts. Check out the top two menu items.
If you want your contacts to be sorted by the first letter of their first name, make sure that Sort Order is set to “First, last”. Display Order is self-explanatory — “John Appleseed” or “Appleseed, John”.
The Short Name menu
Inside Short Name, you’ll notice a few naming options, where the iPhone can show you either only the first name or the nickname of a contact (if available). However, this doesn't really work for your contacts list. Short Names only appear on phone calls, texts, and in the call history menu. Your Contacts list will always display the full names of people, as well as any titles, prefixes, and suffixes you might have entered for them.