Install

sudo apt-get update
sudo apt-get install evolution

On debian Buster the evolution-ews package is only available on buster-backports.

Add buster-backports to your /etc/apt/sources.list

deb http://ftp.de.debian.org/debian buster-backports main

sudo apt update
sudo apt install -t buster-backports evolution-ews

Setup

https://stackoverflow.com/questions/44171006/gtk-3-0-evolution-css-theme-gtk-css

Create file in directory ~/.config/gtk-3.0/gtk.css

 MessageList,* {
         -MessageList-new-mail-bg-color: SteelBlue; #2c5900
 }

save changes made to gtk.css file and restart evolution mail client

You can disable the signature dashes altogether and, if you want:

sudo apt install dconf-cli
dconf write /org/gnome/evolution/mail/composer-no-signature-delim true

I sometimes get no data that flows. I get a message that Evolution is offline. This helps/works for me:

evolution --force-online