I'm an iOS app developer who's learning Japanese. I want to localize my app to Japanese (make a Japanese version of it, basically). For context, my app falls into the "Utilities" category on the app store.
In the user interface of my app, suppose there is a button that says "Save". I want to replace the "Save" text with a Japanese translation. I thought of three ways to do this:
I'm wondering which one of those I should use. The first one is not a verb since it doesn't have the する at the end. So I guess it doesn't really imply that the button does a "save" action? Does this sound like, in English, when there is a button that applies some settings, instead of "Apply", it says "Application"? I think this is not appropriate, is it?
The second one sounds fine, but is it ok to use the plain form here? Is it too informal to be in a Utility app? Should I use the third instead?
I have seen other apps use the first and second form, like 完了 (the "Done" button) and 投稿する (I saw this in the Facebook app's "post" button). But since Facebook is a Social app, I guess it is ok to use the plain form because it sounds like Facebook is treating you like a close friend.
Which one should I use and why?