Yeah, if both parties will be using the same DAW then you can just put the project folder onto a DVD or give them the drive to copy, whatever works.
If different DAWs then you need to bounce stems of the unprocessed, unpanned tracks. Basically go through and set all channels to unity gain (0dB) - make sure unity doesn't mean clipping, if so turn it down a bit so it's peaking at unity at least - make sure all tracks are panned center, remove all EQ, plug-ins, etc. Basically you have to remove any mixing/processing you have done already.
Usually the mixing engineer is not expected to have to edit anything either, if you are unsure about that contact the other guy first, but usually that's how it is. Then if you have a batch export function in your DAW use that, or go one by one soloing each track and bouncing it out so you have the raw, unprocessed track of audio, ready to process. Make sure all of them start and end at the same times! lol
The raw tracks are what the ME will need to import and mix. Extra stuff would be markers, tempo mapping, etc. if the ME wants it.