To add users to your account, you need a business account which requires an active subscription.
First, you need to go to your account settings page. To get there, open the menu and click on the name of your company.
This page will show you basic information about your company, a list of active members and a list of invited members.
To add a new user to your business account, click on new member. This will open a popup asking you to provide the email address of the user to add.
Simply enter the email address of the user and click on the OK button.
An invite will be sent to the user asking them to join your business account.