You need a mac.
Install xcode from the App Store.
Install command line tools xcode-select --install.
Install cocoapods sudo gem install cocoapods.
Install npm and run npm i.
Run npm run build.
Run npm run build before anything else.
An iOS app needs many icon images in different sizes. Use appiconmaker to generate all sizes from a 1024x1024 PNG. 216x216 won't be generated, use another tool to resize it.
For a dev build, run npm run ios and the product will connect to your IP address. For a production build run npm run build which will build the angular/ionic app and copy it into XCode. Navigate into ios/App and run pod install. Run XCode and click run.
Bump the project version in the General tab, Build field. Use the format YYYYMMDD000001 where 1 is the build number for the day (i.e. if you need to build more than once a day, bump this too).
Hit Cmd + B or go to Product > Build. Run Product > Archive. Open Window > Organizer. Select the correct version and validate it with Validate App. Once this is done, click Distribute App.
Head to https://appstoreconnect.apple.com/. Click on Apps, then Gauges: Manage recurring tasks, then Activity. Your build will be in Processing status.
If the command line tools give problems, try this: sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer