I have problems sending and receiving iMessages on my Apple iPhone 13 Pro

Press Settings.

Press Apps.

Press Messages.

Press the indicator next to 'iMessage' to turn on the function.

Press the indicator next to 'Send as Text Message' to turn the function on or off.

If you turn on the function, your iMessages will be sent as text messages if the service is unavailable.

Slide your finger upwards starting from the bottom of the screen to return to the home screen.

Press Settings.

Press General.

Press Date & Time.

Press the indicator next to 'Set Automatically' to turn on the function.

Slide your finger upwards starting from the bottom of the screen to return to the home screen.

Press Settings.

Press Apps.

Press Messages.

Press the indicator next to 'iMessage' to turn on the function.

Press the indicator next to 'Send as Text Message' to turn the function on or off.

If you turn on the function, your iMessages will be sent as text messages if the service is unavailable.

Slide your finger upwards starting from the bottom of the screen to return to the home screen.