storing and watching mp4 files on iPad

Given that you already have mp4 files, instead of trying to import the files to iMovie or rely upon the native Photos or Files App, perhaps consider using a third party player App - or a good quality File Manager App, some of which have excellent player functions built-in.

For a player, of the many available, consider VLC Media Player:

https://apps.apple.com/gb/app/vlc-media-player/id650377962

For a really good file manager that includes excellent player functions, I recommend Stratopherix FileBrowser - Document Manager, or its “pro version” FileBrowser Professional:

https://apps.apple.com/gb/app/filebrowser-document-manager/id364738545

https://apps.apple.com/gb/app/filebrowser-document-manager/id364738545

You might review the extensive online Manual and help files to determine suitability for your needs.

https://www.stratospherix.com/products/filebrowserprofessional/filebrowser-professional-user-guide.php

Once your mp4 files have been transferred to your iPad, you’ll be able to view them at your leisure - without need of a network connection or access to Cloud storage.

You can transfer your files between your computer and iPad in a variety of ways. See:

Transfer files between your PC and devices with iTunes - Apple Support

For Mac, you’ll need to use either iTunes or Finder - as available for your installed version of macOS. For a Windows PC, you you will need to install Apple iTunes and/or iCloud for Windows. You can install and use both on the PC - as they will happily coexist - and provide considerable flexibility in how you move/share/transfer/manage data, photos and other documents between iPad and Apple devices.

iTunes for Windows

Download and use iTunes for Windows – Apple Support

iCloud for Windows

Download iCloud for Windows – Apple Support

Set up and use iCloud for Windows – Apple Support

You might also consider simply copying files to a USB Thumb Drive (applicable for both Mac and PC) and using this to transfer the files to your iPad. If your iPad has a Lightning port, you’ll need an Apple Lightning to USB 3 Camera Adapter with which to connect the USB storage to your iPad:

https://store.apple.com/uk/xc/product/MK0W2ZM/A

Hi, There are a couple of options that you have:

1. Files: A built in file explorer from which you can watch offline
2. Photos: You should be able to open a mp4 file in photos and then be able to watch it offline
3. Google Drive/Other cloud-based storage services

I hope that helps!