Follow below mentioned steps for publishing your app on Apple App Store:
Step 1 : You must have your own Apple Developer account. If you don't have an Apple Developer account, go through:
How to Create Apple Developer account?
Step 2: If you want to list your app as paid app on Apple App Store, you must have to create an Apple App Store Paid Applications Contract. If you have already created the contract, you can skip this step, and follow Step 3:
How to setup Apple Paid Applications Contract?
Step 3: Follow steps mentioned in below FAQ to publish your app on Apple App Store.
How can I publish My iPhone App by myself?