As I’ve created a few apps of my own, I’ve thought more about the placement and naming of buttons.
Take a look at the Save / Add / Done and Cancel / ‘Back’ buttons from five native iOS apps:
Not only do the names vary, sometimes the “Cancel” button is on the right instead of the left.
If course, the names generally relate to the action. You are “adding” a new event to a calendar, “saving” a new alarm, and clicking “Done” on a new note because it is automatically saved, etc. But in some cases, the names could be changed. When creating a new contact, could I not also “Save” the contact?
In the end, as an iOS developer, the best way to approach this would be to think through the action taken and choose words that best describe it. And in general, Save / Add / Done should be on the right and Cancel / ‘Back’ buttons should be on the left.