Lack ability to change line spacing in Apple Mail is been around since 2008. Someone asked this question 11 years ago and it is still the same.
Mail is an important application and the default line spacing is not even less than normal single-line spacing.
Please go to Apple Product Feedback and let them know.
In the interim, I am going to switch to Microsoft Outlook!
They apparently don't think so.
You can provide feedback directly to the Apple Mail product team, but you may also consider that futile too. I can't speculate what internal decisions or lack of them are occurring, or why, within Apple.
Use Outlook if it solves your line spacing issue.
Apple Mail still does not allow custom line-spacing, and even if it did, the Mail client used by the recipient would apply its view rules and potentially undo any line-spacing that you set. Especially if they were receiving plain text, and not rich text.
Perhaps Outlook to Outlook, but not necessarily Outlook to anything else, unless Outlook is sending HTML mail styled with CSS3, which does support kerning, line-spacing, and other word processing associated text features.
Most modern email have HTML and Rich Text so I don’t reall understand the point you are making. We are in 2020, we are working with AI, ML etc. Apple should able to fix a lousy email client!!,!!!!
Mail Line Spacing
