I would like to transfer PDFs, MP3s, and MP4s from Ubuntu 20 Linux to iPhone 16, but I am struggling to find a way to easily do this, and I need your help.
On Android, I'm very used to connecting my phone to my computer with a USB cable, simply copying files over from my computer, locating them via the Files app on Android, and opening them with whatever app makes sense for the file type. I'd like to do the same thing with iPhone.
When I plug my iPhone into my computer via USB, I see two mounts in Files: "Documents on iPhone" and "iPhone". "iPhone" shows pictures and videos from my camera. If I try creating a folder there, I get an error: "Error while creating directory testing123. There was an error creating the directory in gphoto2://[...]. Error creating directory: -6: Not Supported".
In "Documents on iPhone", I see app icons for GarageBand, iMovie, Keynote, Numbers, Pages, Brave, and Firefox. If I double-click Brave or Firefox, I see a Downloads folder. If I try creating a folder there, I get an error: "Error while creating directory testing123. There was an error creating the directory in afc://[...]/Downloads. The connection was interrupted." At that point, I can no longer access ("This location could not be displayed. Sorry, could not display all the contents of "Brave": Unhandled Apple File Control error (2)"), and I have to remount.
Many recommend libimobiledevice and ifuse. I installed those on Ubuntu and can successfully mount my iPhone and copy files to it, but I can't see the files or access them from my iPhone.
I enabled Bluetooth and could successfully pair my iPhone with my computer, but I didn't see any option on either side to initiate a file transfer via Bluetooth, and https://help.ubuntu.com/stable/ubuntu-help/bluetooth-send-file.html.en says "Send Files does not work on unsupported devices such as iPhones."
I don't want to pay for an app to do what I think should be a very simple thing.
I don't want to use cloud services (such as iCloud, Dropbox, Google Drive) because I don't want to upload gigs of data and then download gigs of data. Same applies to email and messaging.
I don't have a Windows or macOS computer to work with.
I don't want to jailbreak my phone.
How can I successfully copy PDFs, MP3s, and MP4s from Ubuntu 20 Linux to iPhone 16 and open them from iPhone?