I made an iOS shortcut that quickly proofreads and enhances highlighted text. You need the ChatGPT app installed on your phone, but you don’t need a Pro subscription.
Highlight some text, like a message you haven’t sent yet. Tap “Share…” in the menu that appears. Choose this shortcut from the options, and you’re finished! It will send the text to ChatGPT, show a preview of the next text, and copy it to the clipboard!