I do all of my mixing from Pro Tools, with a hybrid digital/analogue approach. Very often, I will work with artists who have done their recording, production, and programming in a different workstation. Fortunately, most DAWs make it easy to export and interface with other DAWs, so no matter where your production started, collaborating has never been easier.
To mix your song, I require all stems separated and delivered in two ways: with effects processing (Processed), and dry, with no effects processing (Unprocessed). If there are highly specific processing elements that are integral to the production, such as a sidechain compression scheme or a rhythmic delay, please note these to me.
I also request a rough mix of the song. This helps give me an impression of what you consider foreground and background elements, and lets me know if I’m either missing elements or have parts that were supposed to be muted.
Last but not least, please note to me the BPM of the song.
If you are using Pro Tools, you can just send the session folder.