Why can I send text messages to one iPhone and receive text messages from another iPhone?

This is because the two iPhone share the same Apple ID, which opens the cloud service function of iCloud.

1. Use the same Apple ID, but turn off the iCloud cloud service function.

2. Two iPhones use different Apple IDs, and the other iPhone can directly exit the current Apple ID. Here, take the iPhone 7 as an example, and the specific methods are as follows:

1. First, click "Settings" on the phone desktop.

2. Then open your own Apple ID in the settings interface to enter.

3. After entering, drop down the page to the bottom, and select the "log out" option.

4. Finally, click "Logout" in the upper right corner of the page, and then log in with a new Apple ID.