If your employee count is increased beyond the limit you have subscribed for then you need to upgrade your subscription 

Simply follow the steps below

Step 1: Go to Administration-->Billing Details. 

Step 2: From the Billing overview tab, click on the 'Manage Subscriptionbutton. 

Step 3: Enter the employee count you want to add to your subscription.

Step 4: Select the Subscription Type (Monthly or Yearly) and review the subscription details which are displayed on the right-hand side of the screen .

Note: If your company's subscription is already a yearly subscription then the only yearly option will be available for you.

Step 5: Click the review button to review your subscription 

Step 6: After reviewing click on the "Confirm & Pay" button.

Step 7: You can complete the payment by Credit / Debit Card or UPI / QR Scan or Net Banking

Hope your query is answered !!!