In order to open a mpp, Excel or CSV file in Project Plan 365 directly from Files app you first need to navigate to the desired file. After this, you can either tap on the file (if Project Plan 365 is the default app) or long press on the file, select Share from the popup and then choose “Open in Project Plan 365”. The desired file will then be opened in our app. For more information about Files app please check: https://support.apple.com/en-us/HT206481.