This is a 1999 Suburban, which did not have any aftermarket turbocharger installed. So, the only way it could have been installed is from the factory. So, how do I find out whether it has one? What does it look like, and where would it be installed? (or, what codes should I look for on the stickers)
In your case if it's diesel it has a turbo, if it's gas it doesn't. At least from the factory. Now that is specific to the year make and model in your question. As for what they look like. Nick has a good explanation.
In this picture it's just to the left of the long green tube in the middle of the picture. That tube is connected to the turbo by a short black hose.
Here is a look from the top. The intake tube has not been painted in this picture
Turbochargers look like large snails, and are fitted in the first part of the exhaust, between the manifold and the downpipe. They're often paired with an intercooler, which looks like another radiator...
The Wikipedia page for the Suburban suggests that only the Diesel version of the ninth generation were so fitted (which seems odd from a European perspective, as over here virtually all small trucks have been Turbo-Diesel since the late 80s / early 90s)