Making a difference between test case types

Lets say i am writing test cases for a registration form like: - check if you can successfully register with a taken username - check if you can register with an empty e-mail ... These are functional test cases, right? I also need test cases like: - check if the register button is displayed - check if the text in the register button is "Register" - check if the logo is displayed Whats the type of these test cases and do i separate them from the test cases above in another test case document?