How do I change an image's background from white to transparent on iOS?

Images with a transparent background (i.e: a .png file with a transparent background) can be uploaded to use in your video.  

However, you may experience that when you upload images from an iOS device, your image will appear with an opaque white background instead of the expected transparent background. 

iOS devices (iPhone/iPad) running iOS version 13+ do not support transparent backgrounds. The resulting image will appear with an opaque white background instead. 

You can work around this by uploading the full-resolution file in its original format. 

To upload an image with a transparent background from an iOS device:   

1. Select Settings on your iOS device. 
2. Select your name at the top of the settings screen to open your Apple ID settings. 
3. Select iCloud to open your iCloud settings.
4. Select Photos.
5. Select how you'd like to save your photo's original format. 
   • Select Sync this iPhone/iPad if iCloud is not turned on for your photos. This will sync the original format of your photos from your iOS device to your iCloud drive.
   • Select "Optimize iPhone/iPad Storage" to keep the original formatted photos in your iCloud drive. This will replace the full-resolution files on your iOS device with smaller files. 
   • Select Download and Keep Originals to keep the full-resolution files in their original format on your iOS device. However, this will take up more storage space on your iOS device. 

Read about using iCloud photos from Apple Support at ‘Set up and use iCloud photos’.