In order to publish your app on the Apple App Store you are required to activate a Developer Account for $99/year.
You can find step-by-step instructions here:[https://developer.apple.com/programs/start/standard/]
1 - Sign in with your Apple ID on the Apple Developer Platform
2 - Enroll as an individual or an organization
3 - Fill in the form and review
4 - Purchase the program you prefer
5 - Active your Developer Account
You are now ready to submit your App to the Apple Store for review before it is published and available for download or purchase by users.
Please note that it may take 7-10 days for your developer account to be successfully activated.