Why can't text messages be sent out?

You need to turn on the MMS function to send pictures, and then you need to set MMS to send MMS normally.

Take the iphone as an example. The specific steps are as follows:

Step 1: First select Settings-General-Cellular Mobile Network-Cellular Mobile Data Network.

Step 2: Open the settings and find the information.

Step 3: Open the MMS from the message.