How to set the background of Apple mobile phone matting?

This is how I set my Apple phone to change the background. Open my Apple phone, enter the photo application, click the photo editing icon, select the cropping tool, click the finish button, open the photo application, and click the edit button in the upper right corner. Select the cutting tool, click the Finish button to open the main cutter application, and then click the Smart Cutter button. After cutting, you can choose the background template provided by the application or your own photo as the background. After setting the background, click the "Save" button to save the silhouette and the photos with changed background to the album.