Access the Tool:
Sign up required to access tool: Yes
Link to support page: https://protonmail.com/support/
Link to GCA Community Forum: https://community.globalcyberalliance.org/tags/c/cybersecurity-toolbox/communicate-securely/protonmail
Additional Notes: The default settings may not be the most appropriate and should be reviewed subject to user circumstance.
Link to Tips and Tricks for usage and forum to ask any questions: https://protonmail.com/support/categories/tipsandtricks/