I'm going to elaborate on what Mussar and Mohonad said.
Do not solo your tracks and export them individually! If you've got any effects that rely on other things being played this will ruin them. For example, if you've got a chord that is sidechained to your kick and ducks when the kick plays, you can solo the kick and render it, solo the chord and render that, and then when you throw them back into a new project they won't sidechain. This will also cause problems with any sort of mastering plugins that mess with the overall song's volume. If this is what you want then yes, solo each channel.
However, if it's not, and you do want to create a puzzle that can be easily put back together to form your song exactly as it's meant to be played, then export and select "Split Mixer Tracks". This will separate audio files for each mixer track, but you have to remember that if you have anything that's not feeding into the mixer it will not come out on its own (it will appear in the "master" file which a rendering of the master channel, but not as its own channel).
And finally, bounce to .wav for producers (lossless quality), which is probably who you'd be sending stems. Bounce to .mp3 to share it with friends or test it out on other systems or whatever, but that'll compress it.
