Yes. On recent versions of iOS you can set a short audio file as a ringtone straight from the Files app: open the file, tap Share, and choose Use as Ringtone. Keep the file to 30 seconds or less. On a computer, you can also sync a ringtone file to the iPhone with Finder on a Mac or iTunes on Windows.
GarageBand is only needed when your iPhone does not show Use as Ringtone, or when you want to edit the sound yourself. If you would rather skip editing altogether, Ringoz makes a finished 30-second ringtone from your words, so there is nothing to trim.
Related questions
How do I make a custom ringtone on iPhone?
Get a sound of 30 seconds or less, add it as a ringtone, then pick it in Settings.
How long can a ringtone be?
Keep it to 30 seconds; iPhone tools trim to that, and calls rarely ring longer.
How do I make a ringtone from text?
Turn the words into audio (spoken or sung), keep it short, set it as a ringtone.