Bitwarden has updated its online password manager to include transmitting text and files (100 MB upload limit) securely over the Internet.
Bitwarden Send empowers teams and individuals with a secure, simple way to share information directly with another person. Easily transmit text or files including passwords, billing credentials, or business documents fully encrypted. A Send object can be further protected with user-configured parameters, including:
A deletion date
An expiration date
A maximum access count
A password requirement
Option to disable
As with everything else Bitwarden does, files and text transmitted using Bitwarden Send are end-to-end encrypted and zero-knowledge (so Bitwarden does not have access to the content that is being sent and cannot decrypt or access the content).
Bitwarden posted a thorough explanation of how the Send service works.