https://osxdaily.com/2014/05/06/change-default-mail-app-mac/
How to Change the Default Mail App Client in Mac OS X
Feb 26, 2018 - How to Change the Default Mail App Client in Mac OS X
how to changedefault mail app
https://proton.me/it/support/ios-default-email
How to set Proton Mail as your default email app in iOS | Proton
Learn how to set Proton Mail as your default mail app on your iPhone or iPad to open email address links in Proton Mail automatically.
how toproton mail