Step 1:
Go to "Billing" section by clicking on the profile picture at the top right corner in the Dashboard and then you will get navigated to this screen.
From here you need to select "Subscription"
Step 2:
Click on the Update Subscription
Step 3:
Then you will get navigated to this screen
Select the number under "Social Planner Seats" to add users who will manage your social media post scheduling and click on Update Subscription.
