Select your project
If you don’t have any project, create one
Open the left menu and select API & Services
Click ENABLE API AND SERVICES
Search Maps SDK for Android
Click Enable button to enable Maps SDK for Android
Open left menu > API & Services > Credentials
Click "Create Credentials" and then click "API key"
Your API key will be created. Copy the API key and save it on your side
Click RESTRICT KEY
You may change API key "name" for your reference on the top and then select "Restrict key" radio button at the bottom
Search Maps SDK inside the restrict key and select the checkbox of "Maps SDK for Android" and click "Save"
Share with us the API Key you have copied earlier.