On iPhone and iPad
There are 2 options to add your logo to your photos.
1- The first option offers you to automatically add your logo to each editing photo.
As a Pro user, you can
Import your logo and edit it
Add it to your Favorites (tap on the yellow star)
In "My Favorites asset" section, select your logo
If you want your logo to appear on all your images:
Enable the "Add automatically my logo" feature
Your logo will appear automatically on your next edited images, at the exact same place you choose when you added it to your Favorites
2- The second option offers you to add your logo to your photo as an image.
Once you're editing your picture, simply tap
"+" to insert an object
select your logo in your library
position your logo as you want
Note that you can go to your Content tab, tap on the 3 dots of your creation to "Duplicate" it and "Apply to multiple images".
The first option is not available yet on Android. It will be soon.
Alternatively, you still can use the second option.