Identifying the correct phone number to use in "Messages"

Hi, TheRosstaman.

Thank you for reaching out on the Apple Support Communities. If we understand correctly, you’re wanting to know how you can tell which number on a contact card is the number to choose when several numbers are saved for that contact. For example, in your screenshot, all four numbers appear but it doesn’t differentiate between the numbers in the list. 

There isn’t a way to label those numbers when you’re sending a text from the Messages app, but these hints may help.

• Numbers associated with iMessages will appear in blue while other numbers will appear in green. If the contact in your example has an iPhone for mobile, that number will be blue while the fax, pager, and home (if it’s a landline) will all appear in green. 

• The last number chosen for text will always appear on top. You may need to start the text conversation from the contact card the first time you send the message, but after this you can either reply directly from the conversation thread or choose the last used number on the top when you start typing the contact name in your New Messages box. 

This article may also help:

Send and receive text messages on iPhone - Apple Support

Cheers.