In order to compile your app for ios you have to run the following command in the terminal.
eas build --platform ios
It may require to login to your expo account via the terminal
Then it will ask you some question answer the questions correctly and then your app will be pushed to the official expo website and you will be queued for build then after some time when it will be your turn your app will be auto build by expo and after the build is successful the compiled app will be pushed to the amazon s3 that you can later easily download from your expo account. For more information visit the official expo build docs.
Now when your app is ready you can directly upload the app to the Apple App Store. Please check Apples's official guide for uploading app to Apple App Store.