Apps are installed from the Stripe App Marketplace. If you’re an Administrator for your account, you can use the Marketplace to find the listing page for the app you want to install, click the "Install app" button on the top right and then review the permissions requested by the app developer, as well as the app’s privacy policy.

Apps which have UI Extensions will be available on the right-hand sidebar of your Stripe Dashboard.

Apps are installed only for the account which is currently active in the Dashboard (of which you must be an Administrator), so if you have multiple accounts, you’ll need to switch the account you’re viewing by clicking on the name of your Stripe account in the top left-hand corner and then selecting the account you want to switch to.