Unable to access .tpk file in ArcGIS Field Maps for iOS

Answer

• Tile packages can be created and published for offline use with ArcGIS mobile apps. For reference, see: How To: Create and Publish Tile Packages for Offline Use with ArcGIS Mobile Apps
• The process to sideload mobile map packages (MMPKs) can be found in this reference: Configure the mobile app—ArcGIS Field Maps | Documentation
• If you use the Files App and the MMPK has been copied to it, you must be signed into your IOS device using a valid Apple ID to access the MMPK. If you are not signed in, it is likely that Field Maps has not created a folder in the directory.