Use Your Keyboard to Move Your Cursor
If you want to fix a few typos in an important message, you can turn your iPhone’s default keyboard into a fully functional trackpad for your cursor. This will help you move your cursor around the text you just wrote and easily go to the words you want to change.
All you need to do is press and hold the spacebar on your keyboard and wait until it fades out. Then, without lifting your thumb, move your finger around the keyboard to position the cursor to wherever you want.
To exit this mode, just lift your finger, and your keyboard will go back to normal.