"Shadowrunning" is a very broad term, like adventuring.
The usual shadowrun is breaking into a facility and get something, or someone, out. Or to assassinate/blow up something.
But in the end, a shadowrun can be anything people pay you for. It could also involve investigating a crime or news story or even "good old dungeon crawling". It is also easily possible to play something else than Shadowrunner, for example cops or journalists.
Staying with traditional shadowrunning, a run usually consists out of 3-4 steps.
1. Making the deal. This can be an adventure in itself when the client insists in meeting at a unfamiliar location, like a celebrity party. Also there is always the chance that something goes wrong or that it is a trap.
2. Legwork. This is information gathering. Finding out who or what your target is to plan your attack, but also investigate the circumstances of the run and your employers allegiance. Not everyone (or rather nearly no one) is honest and upfront about who he is, and not knowing can get you into trouble or killed fast.
3. The run itself. Breaking and entering, shooting, sneaking, persuading. And of course, no plan survives contact with the enemy.
4. The delivery and escape. Once you have what you wanted you have in many cases to deliver it to your client. So now not only are you hunted by whoever you ran against, but if your client is going to betray you it is now. And even after the exchange you have to go undercover until it is uneconomical to pursue you further, something you can speed up with a little blackmail, etc.
Not all runs contain all those steps and it also depends on the preference of the group.
If you are not doing a run there are still a lot of things to do:
- Maintaining contacts.
Knowing people is very important in Shadowrun. And if you want to stay on their good side, or get there, you have to do some favors for them. This can be as simple as just spending a night at a hotter club (VIP of course) or can take the form of a Shadowrun in itself.
- Get gear.
Face it, even in the future portable tank cannons are not sold in your local weapon shops and the black market can only get you so far without you having to jump through hoops to get what you want.
- Do a astral quest/deep dive
For (techno)mages to get stronger or to get some nifty benefits you can't get anywhere else you can do this quests which, thanks to the amorphous form of the astral or the matrix can be pretty much anything.
- Survive
Yes, that can be quite a problem. When you are hunted by the law, or worse, have no cover ID ready so that you can even buy a candy bar (100% soy!) from a vending machine without setting off alarms all over the city and the local gang just wrecked your last safehouse "for teh lulz" just surviving can be an adventure itself.
Have I mentioned that the rats in Shadowrun are dog sized (which incidentally are among their favorite food, next to everything else).