How do I get my initials beside my texts when I send them

Start by going to Settings>Contacts>My Info. Is your contact card selected? If not select it. If you don't have one, add yourself to Contacts.

If you have a picture in your contacts, you'll see your picture, not your initials. To see the initials, you'd need to remove the picture.

Note that what you see is not necessarily what your recipient sees. If you want other people to see your photo, go to Settings>Messages>share Name and Photo.