Beagles do bark a lot although they do not bark as often as other dogs unless they see a stranger or something else they are not familiar with or they are left alone.
When left alone for long periods of time especially outside the beagle will usually begin howling and barking until someone comes home.
But other than that the beagles as long as you keep playing with them, give them love and attention and they don't see strangers then the beagles are pretty quiet dogs when it comes to barking.
Beagles will usually only bark when necessary so you shouldn't have to worry about the beagle barking too much especially if you live in an apartment or other place that has noise ordinances.
I had two beagles as a kid and they were very loving, gentle and playful dogs and as long as you treat them with love, care and respect the beagle will show you the same love, care and respect and are quiet dogs unless they need to bark.