Depends on the kind of beverage - tea or coffee-based drinks typically have naturally-occurring caffeine (unless specifically decaffeinated).
i think people add caffeine too soft drinks to make it more addicting.
caffeine
Caffeine is a stimulant that can cause an elevated heart rate and increases alertness. Cola soft drinks that are decaffeinated do not have any caffeine added to them.
because of all the caffeine and sugar that is in them
caffeine
Caffeine is found naturally in coffee, tea, and chocolate. Colas and some other soft drinks contain it.
Among common soft drinks, caffeine-free options like caffeine-free Coca-Cola or caffeine-free Diet Coke have no caffeine. However, if considering caffeinated drinks, root beers, such as A&W and Barq's, typically contain very low levels of caffeine compared to colas. In general, most lemon-lime sodas, like Sprite, are also caffeine-free.
Coffee...tea...chocolate and many soft drinks such as Coke and Mountain Dew. some aspirins contain caffeine too
Mountain dew
caffeine
caffeine
Many soft drinks contain caffeine some examples are Coca Cola, Pepsi Cola and Mountain Dew. "Energy" drinks also contain caffeine. Just read labels.