Please note that this method of verification is deemphasising and video verification is the new norm.
https://support.google.com/business/bin/request.py?contact_type=verification_code_issues
Google support will ask for 3-5 photos:
- The business' storefront as seen from the street and/or in front of your store
- Signage showing the name of the business and its entrance
- The inside of the business, as a customer sees when entering
- If available - a link showing Google Street View imagery of the street and/or neighborhood in which your business is located
- If applicable - name and website URL of the venue in which your business resides (e.g. shopping mall)