When my app starts on my device xcode says it uses 3.4MB of memory.
When I use every feature in my app on my device xcode says it uses 14MB of memory.
When i submit my app on the appstore, when a user goes to download it, under information what will be the size of my app?
thankyou
That's your RAM usage, and has nothing to do with the download size.
The download size will be the size of all the png images/videos/etc in your application, plus a tiny bit more for the actual code.
To find out the exact number, do an "archive" build, and in the organiser there is an "estimate size" button.