BetterDiscord
Open Settings > Themes > Themes folder and copy the file downloaded here
Replugged
Click here and confirm the install in the client
Vencord
Copy https://nyri4.github.io/Couve/betterdiscord/couve.theme.css into the box in Settings > Themes > Themes tab
BetterDiscord
Open Settings > Themes > Themes folder and open couve.theme.css
Replugged
Navigate to betterdiscord/couve.theme.css on Github, copy the content and paste it in Custom CSS, then modify variables
Vencord
Navigate to betterdiscord/couve.theme.css on Github, copy the content and paste it in Custom CSS, then modify variables
Of course all credits goes to abUwUser/A user, the original creator of this theme and AAGaming that maintained the theme, see his github profile here