Currently we don't have an app in the Apple or Android stores. However, now it's easier to access your Folio without having to go to my.folio.co every time.
For Iphone / Ipad:
Open Folio on your favorite mobile browser, click the “Share Link” button and then click “Add to Home Screen.” This action will create an accessible “app” you can use for simpler mobile access.
More details in Apple Support user guide
For Android:
To add a website as a quick-access icon on your Android home screen, open the site in Google Chrome, tap the three-dot menu, and select "Add to Home screen". This creates a fast-access app-like icon in your mobile home screen.