Hello! Nice sentence. Here is the corrected, easy version:
Capybaras are friends with everyone. They are not afraid.
Step-by-step (very simple):
- "Capybaras are friends with everyone" is already good — it tells who and what.
- The second part needs the verb "are." Say "They are not afraid." You can also say the short way: "They're not afraid."
- Use a period (a dot) between the two ideas instead of a semicolon. A period makes two short, easy sentences.
So the final simple sentence to remember: Capybaras are friends with everyone. They are not afraid.