To grant access to your Google account you need to:
 
1. Login to your Google developer account.

2. Click on top left menu. 
3. Go to IAM & admin -> IAM -> Here you can add/remove users and manage permissions.
4. Click “+ ADD” button that is displayed at the top of the screen and fill in the form as follows and click “Save” button.
– New members “sales.easytaxioffice@gmail.com”
– Role “Editor”
– Tick checkbox “Send notification email”
5. All done.

 
Learn more about Google permissions here.