Nowadays most of the people use Whatsapp, Facebook, etc. for communication, and gmail, dropbox, etc. for file sharing. We use them because they are very popular & common, but the problem with these apps is that, they are NOT END-TO-END ENCRYPTED, what I mean by end-to-end encryption is that they can track our location, they can read our messages, or in simple words, they have full control over our account. Sometimes not being end-to-end encrypted can cause a lot of issues, for instance, if James wants to send his bank account's password to his wife, and a hacker is intercepting his messages, then the hacker will also beable to read James' password.
But if a hacker isn't a problem for you, then there is another problem, the employees of the company will also be able to read our messages, and DO WE TRUST THEM?! NO!, because we don't know them.
The best solution for insecure sharing of file/text is to use end-to-end encrypted services like Telegram, Onion Share, etc.
1. Telegram:
Telegram is a freeware, cross-platform, cloud-based instant messaging software and application service.
The service also provides end-to-end encrypted video calling, file sharing and several other features. The main benefit of using Telegram is that, it is end-to-end encrypted for the users.
2. OnionShare: OnionShare is an open-source tool that's available for Linux, Windows, and macOS. It lets you securely share files directly from your computer to the receiver without revealing your identity in the process because it uses end-to-end encryption.
FULL GUIDE FOR ONION SHARE