Exactly what can be searched in 'search for' area

I hope this isn’t a foolish question.

Exactly what can site visitors type in the ‘search for’ box?

Listing name, description, key words, etc.? If they type computer will it just find the word computer in the Listing name or will it actually look through all the listing descriptions (or more) to find the word computer.

I want to title the ‘search for’ area something more descriptive, like find business or find members, but I don’t want to do that if the search allows for more than that.

I didn’t find anything in the documentation area that described this.

Thanks,