You can access the My Subscription window from the switcher. 

From here, you can edit your plan details from the Manage Plan button. 

Underneath this, you will be able to upgrade to a higher billing frequency. 

Once you choose the updated frequency, please press 
Update Subscription at the bottom to ensure your changes are reflected. 

Note -  if you request a change in billing frequency from lower frequency to higher, the change will only be reflected after the current billing period is over. 

If you are an offline paying customer (you do not have a saved card in your subscription and pay through a different mode), you cannot change billing frequency online. Please write to for more details.