App Engine is regional, which means the infrastructure that runs your apps is located in a specific region, and Google manages it so that it is available redundantly across all of the zones within that region.
Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your apps are run. You can generally select the region nearest to your app's users, but you should consider the locations where App Engine is available as well as the locations of the other Google Cloud products and services that your app uses. Using services across multiple locations can affect your app's latency as well as its pricing.
You cannot change an app's region after you set it.
If you already created an App Engine application, you can view its region by doing one of the following:
gcloud app describecommand.
Open the App Engine Dashboard in the Cloud Console. The region appears near the top of the page.
To select a region, you create an App Engine application in your Cloud project. See Managing Projects, Applications, and Billing for details in your language for either the standard or flexible environment.