Take the iPhone 8 as an example. The specific operation includes the following steps:

First, open "Photos" on the phone's desktop.

2. Then click "Edit" in the upper right corner of the photo to be operated.

3. Click on the "More" sign in the lower right corner.

Fourth, select the "Mark" option to proceed to the next step.

5. Click the plus sign in the lower right corner and select "Text". A text box will appear on the icon.

6. Finally, click "Text Box" to select "Edit", and then enter the text to complete the operation.