Adding Multiple Accounts to Twitterrific (iOS and macOS)
How do I add multiple accounts?
Tap on the "Accounts" button in the sidebar, or tap and hold on your user avatar at the top left of the application, to bring up the Accounts screen. From there, press the + button in the upper right to add an account that's not on your device and display a sign in screen. This screen will take you to Twitter's OAuth webpage to grant Twitterrific permission to access your account. Once you do that, you'll automatically be returned to Twitterrific.
Press ⌘, to open the preferences panel and then click the Accounts panel to open it. Press the + button to add a new account and then enter your Twitter account info. You'll be taken to Twitter's OAuth webpage to grant Twitterrific permission to access your direct messages. Once you do that, you'll automatically be returned to Twitterrific. You can re-order the accounts by promoting one account up in the list using the ↑ button at the bottom of the account pane.