To set up an Office 365 Tenant go to this address:
https://products.office.com/en-GB/
For this example, we’ll set up an Office 365 Enterprise E3 subscription, as this comes as a trial. You can set up a tenant without it being a trial first, which can be converted later on to a full subscription on whatever plan you need.
Follow the links for:
“For Business” >
“See Pricing & Plans” >
“See more plans & pricing” >
Then select Enterprise E3.
At the bottom of the features list for E3, you will see a “Free Trial” button. Select this and we can begin the process.
Main thing to remember here is that the Company name must be unique. If this is a test tenant account, then DO NOT use your intended production environment domain name as this will make it unavailable.