So I've done some research around this question on Google's G Suite site and can't tell definitively if the following is possible:
Scenario:
I have an email address on a non-G Suite server.
Let's call it "sales@alias.com"
Question:
If I open a G Suite account will I be able to use the exact same email address, sales@alias.com, on G Suite?
I do know I can migrate existing mail and calendar information to G Suite but I want to know if I will be able to use the exact same email address I am currently using.
Best Answer
Generally, yes.
If you own/control the domain alias.com, you can move it to G Suite and then either create an account sales@alias.com or create some other account like russell@alias.com and add the sales@ address to it.
If you only have an account provided by someone else in the alias.com domain that you do not control, you can still use G Suite with your own domain somethingelse.com, create an account for yourself russell@somethingelse.com, and then from within that account enable sending and receiving of email through sales@alias.com.
In the first scenario, you actually move the address to Google. In the second, Gmail acts as an email client.