Saving a checkbox value or name on firebase/firestore?

I am building a social network project, in which people have to select favorite topics, i am trying to store the value(or name) of a checkbox once it's checked, so it can be called and shown later on.

Is there a way I can store this in firestore as part of a user profile? Right now the account creation section allows me to store the name, email and username of the user, but I'm not sure how to store the checkbox value.

Thanks! I've been learning js for a few months, so please don't be so harsh on me, maybe this is a basic them i've skipped or didn't understand correctly. Thanks in advance!