1. To create an email alias with a Google domain, go to domains.google.com.
2. Ensure you’re under the correct google account (this changes itself sometimes.) 
3. Click My Domains on the left.
4. Click Manage.
5. Click Email on the left.
6. Click Add an email alias
7. Adding an alias example: 

[email protected] would forward automatically to [email protected]

This is a free option for people to reach your staff without having their personal email addresses.