It's easy! You can upgrade your subscription to a new plan or an annual plan at any time through your account's dashboard. You will find it under Accounts -> Billing. Upgrades take effect immediately. Any unused days or months in your current plan will automatically be credited against your new plan.
To note, when looking at the dashboard, both monthly and yearly plans will appear selected as "Your Plan". This is because "Your Plan" just indicates which tier you are on, not which billing cycle you are on.
Even though both plans appear selected, you should still be able to click on the opposite billing cycle to make the switch. If you experience an issue, we have recently discovered a bug when using the Safari browser, so please try to complete the upgrade in another browser such as Chrome or Firefox.
For additional questions, please visit shinyapps.io or email: firstname.lastname@example.org.