You can use the simple phone background (INT. CELLPHONE - DAY) and use the NARRATOR dialogue boxes with the character name:
NARRATOR (CHARACTER)
Dialogue.
Or you can use overlays for each text message like this. Here’s how to use overlays: A Guide to Using & Animating OVERLAYS
Or you can set the format to phonetext (it can be glitchy maybe since it hasn’t been officially released): Check it out here