I use Google Drive, so I can only speak to that. If I'm logged into my email on another person's computer then I'm already logged into drive. Similarly, for me

I use Google Drive, so I can only speak to that. If I'm logged into my email on another person's computer then I'm already logged into drive. Similarly, for me having a file in my inbox is effectively the same as having it in Google Drive. I can access it from any device. I guess I'm outside your target audience. I wish you the best of luck.