how to remove buttons above window

This may be an option in your theme. Look for something related to subnavigation or submenu.

If you don’t find that, the ‘quick-and-dirty’ way is to edit your style.css.

You should create a Child theme to make your changes. If you do not, all of your changes will be lost if you update your theme.

Edit style.css and change the last line from this:

</style>

to this:

#subnav { display: none; }