Your phone can automatically caption videos, podcasts, audio messages, and recordings.
To enable captions, go to Settings > Live Caption and turn it on 
Then, to quickly turn captions off/on:





To remove the captions, go to Settings > Live Caption and turn it off 
Battery use: When your battery gets low and Battery saver is on, Live Caption automatically turns off.
You can hide or show:




Real-time text (RTT) lets you use text to communicate during a phone call. Your phone sends text as you type and the recipient can read your message while you write.
RTT:


Tap the real-time text option and turn it on or select when you want it to appear.

Call the number.
While the phone rings, the other person's screen displays an RTT indicator.
After the other person answers, enter a message in the text field.
The text that you enter is visible to the other person as you type.


For text-based communication, you can use text messaging and email.
If you prefer to connect to a TTY device:


Select a mode: