Hi, @jovianne
After you login in, on the left top of screen, there is a option “Customize”, click it, navigate to “Menus/Menu Locations”, select “Primary Menu” to “-Select-“, then the top right menu will disappear.
If you have more question about wordpress, please @ my-name, I am glad to help you.
Hello @arthur2sereno
Thanks for your help and resolved my problem :))