There are many characters named “Captain Marvel”, and I guess it can be confusing to people who aren’t experts. So here’s an orientation (Wikipedia would say “disambiguation”) page for your convenience.
On the DC-ish side
Captain Marvel (Billy Batson), the big red cheese. An older gisted profile of the World’s Mightiest Mortal, pre- and post-Crisis. Very old notes, though.
The same as above, but in the possible Kingdom Come future.
The 1941 Republic serial adaptation of this Captain Marvel.
The version in the 1970s Shazam! TV show
Captain Marvel, Jr. (Freddy Freeman), an ally of DC’s Captain Marvel (very old notes, too).
Mary Marvel, another close ally of Captain Marvel. Quick, old notes.
Thunder (Cece Beck) — not to be confused with Black Lightning’s daughter Anissa Pierce — is the Captain Marvel of the 90 th century and, briefly, of the 30 th.
Miracleman, created in the UK once Fawcett’s Captain Marvel stories could no longer be published.
Captain Terror, a made-up evil version of Captain Marvel. On the Marvel side