To add your logo to your account, click your name in the top right corner and select Account.
Scroll down until you see Logo. Click the Choose File button and upload your logo. Hit Save Information at the bottom of the page to save your selection.
Your logo will show up in the top navigation bar on the desktop as well as on the daily check-in screen for your clients within the app.
While you can use any type of logo you want, the ones that look best have a white background and are horizontal (wider than they are tall).