Hello there!
Here some relevant tutorials and articles:
https://www.google.com/amp/s/instabug.com/blog/how-to-submit-app-to-app-store/amp/
https://developer.apple.com/app-store/submitting/
https://codewithchris.com/submit-your-app-to-the-app-store/
After you finish your application you can submit it to a big publisher / store like Play Store or App Store and it may come with fee. You can use Google to find how to publish it correctly it's not an easy process.
