Update changing-plans.md (#161)

docs/billing-and-invoices/changing-plans.md

@@ -8,5 +8,5 @@ To upgrade or downgrade your plan, go to your billing portal:
 1. Click **Settings** in the dashboard menu.
 2. Scroll to the billing section and click **Open your billing portal**.
 3. Click **Update plan**.
-4. Choose whether you'd like to pay monthly or annualy and pick a plan from the list.
+4. Choose whether you'd like to pay monthly or annually and pick a plan from the list.
 5. You will be billed pro rata taking into account your current plan, the time left in your current subscription period and the new plan you select.