OnePlus 7 Pro 5G
Setting up your phone for text messaging
A text message is a message that can be sent to other mobile phones. Your phone can send and receive text messages as soon as you've inserted your SIM. If this isn't the case, you can set up your phone for text messaging manually.
Press the message icon.
Press the menu icon.
Press Settings.
Press SMSC number.
Key in +447958879879 and press OK.
Press the Home key to return to the home screen.