You already have the Entra ID environment set up with the Entra ID connector Sync to have On-Premises AD Account added.
You have the credit card or purchase method configured on Entra ID env.
You have sufficient budget. (1 Teams license per user costs about $9 per month)
Setup
Go to Microsoft 365 Admin Center via the Entra ID Administrator ID. https://admin.microsoft.com/
Go to Marketplace.
Select “Teams” in recommended Products.
Get Check out.
It is not recommended that you select Free Trial. It mandates the 25 licenses to you. From next month after Free Tral passes, you will have 25 licenses automatically charged. Please select “Change” in order to specify the exact license number.
Specify your necessary license count. And click “Buy”.
You confirm you make a purchase.
Click “Place order” at right top.
Purchase process will be treated.
Once the ordering process is completed, it shows the success.