An app ID is a string used to specify an app, or set of apps.
An app ID has two parts: the team ID followed by the bundle ID search string. The team ID is a 10-character string generated by Apple. Each development team is assigned a unique team ID used to identify all your apps. A bundle ID search string is traditionally a reverse-domain-name style string.
The following guide will show you create an App ID in the iOS provisioning Portal. To create an App ID, you need to have an Apple Developer account and be a member of the iOS Developer Program.
1- Log in Apple Developer Center, then click “Certificates, Identifiers & Profiles”.
2- Click “Identifiers” under iOS Apps
3- Click on the “+” sign near the top right corner to add a new App ID. Create the App ID you want to use as well as the description you want to give it. After that you will be brought to the confirmation screen. Hit submit once you looked over it.
4- After that you will be brought to the confirmation screen. Hit submit once you looked over it.
5- In PubCoder go to Project Settings and insert the Bundle ID in the App Identifier field.