What are the requirements before trying to publish an application?
To distribute an application on the App Store, you need to subscribe to an Apple Developer account. The Apple Developer Program annual fee is 99 USD.
If you don’t already have an Apple Developer account you can subscribe your account here: https://developer.apple.com/programs/enroll//
Once you’ve completed your enrollment in the Apple Developer Program, you can sign in to iTunes Connect with the Apple ID you used to enroll. iTunes Connect is where you manage your App Store apps, see your sales reports, manage your iTunes Connect users and testers, and more.
For more information about the complete process use the link below: https://itunespartner.apple.com/en/apps/overview
To distribute an application on the Google Play Store, you need to subscribe to a Google Play Developer account. There is a $25 USD one-time registration fee.
If you don’t already have one you can subscribe your account here: https://play.google.com/apps/publish/signup