Automatic signing is a target setting that allows Xcode to manage signing assets for you. The signing settings are located in the General pane under the heading Signing in the project editor. To enable automatic signing, select “Automatically manage signing.”
If you enable automatic signing, Xcode does the following for you when needed:
Creates your signing certificates
Registers connected devices
Creates and edits App IDs
Manages provisioning profiles
Edits the entitlements and information property list files
If you choose manual signing, you’ll need to sign in to your developer account at developer.apple.com/account to perform some of these steps yourself.
Important: All targets in a bundle should use the same signing certificate. If you select automatic signing for one target, you should select automatic signing for all targets in your project.