Here are the steps you need to follow to switch from a monthly plan to an annual plan:

Step 1. Access your Billing page

Step 2. On the Billing page, you’ll have to select the option "Yes / Show annual plans"

Step 3. Now you’re going to see this page showing all the annual plans

You can switch from a monthly plan to an annual plan by clicking on the “Change plan” button

Final Step. After clicking on “Change Plan” you’re going to see a message saying:

“Are you sure you want to change your plan?”

Click on the “Yes, change it!” button to conclude.