Somebody, anyone, everything, etc. are indefinite pronouns.
We use -body, -one, -thing, -where to refer to people, places and things in a general way. We write them as one single word, apart from no one, which can be written as two separate words or with a hyphen (no-one).
The differences in their meanings are the same as the differences between some, any, every and no. We use them all with a singular verb:
Is anyone helping Claire with the washing up?
Everybody makes mistakes.
I’m looking for somewhere I can store my bike.
-body and -one
-body and -one mean the same thing. In informal contexts, we use indefinite pronouns ending in -body more often than pronouns ending in -one. The forms with -one are more common in formal writing:
Nobody was interested in the talk. (or No one was…)
Everyone started to clap. (or Everybody …)
Somewhere nice, nothing much
We can add an adjective or adverbial expression to these indefinite pronouns to make them more specific:
A: What did you do at the weekend?
B: Nothing much.
Are you thinking of anyone in particular?
Is there something else I can do to help?