B4J Question User friendly way to transfer a file, from computer to phone?

Hello,

I have a software that makes a video. I need to transfer that video to a client. I would like that process as user friendly as possible. I'm thinking of several options:

Online:
- Send the file by email (Which is the current solution)
- Upload file to an FTP, show the URL as a QR code to the client
Offline:
- Bluetooth

In the current solution, the email, it's good because it requires minimal input. But to my surprise (i'm getting old I guess), people don't use email ? Teenagers don't even know their email addresses!?

I would prefer an offline solution. I ask the community because maybe there are other more user-friendly solutions for that. The idea solution would be a button "send it to my phone"!

For example, I've seen a photo printer in a shopping mall that work with a Wifi hotspot or something like that. People just connect to that hotspot, go to an IP address and upload the files.
I've seen other apps that use near field I think?

I'd like something similar, but the other way: I need to send a file to their device.

Thanks for your help!