If you add a user without a license, they will have the ability to request licenses when they log in. Your pending requests can be viewed on your user page. If you have outstanding pending requests, click the "pending requests" button in the right corner.
Once you click the button, you will be able to grant or deny licenses
If your company is a bigger organization and you’re worried about getting a large amount of license requests in your email every day, you can navigate to the “Notifications” tab and select to “Receive a single weekly digest of license requests” instead of instant notifications. You can assign group administrators to receive requests for specific team. Learn more.