How I can understand and use the word correctly specifically at English learner as second language for example I know what is mean is to cancel something, but how can I use it

Greetings Batla,

as you correctly mentioned, "to annul" something is to cancel it. The difference between "cancel" and "annul" is that the second one is mostly used for formal purposes and situations. For example, a formal document or agreement, a marriage, or anything that has to do with the law.
Example sentences: They had to annul their marriage due to personal differences. The company didn't follow the agreed terms, so the supplier annulled the contract.
We hope this helped!

Dimitra M.
Lexary Staff