We’ll enable adding mailto syntax formatted links (mailto:firstname.lastname@example.org) in the FilePicker via the “From a link” tab. This is already supported in the Page picker (Ctrl+K) in the rich text editor (RTE) on modern pages.
An error occurred while saving the commentBjørn Christian Borgen commented
Also looking for the option to add mailto links on our Sharepoint Online site. Why MS haven't implemented this is really strange to me.....