You mean the burger menu that shows on the small devices to access the menu. I guess it is not a good idea to hide that menu, instead, we can remove the sticky of that element so that it moves up when scrolling the content.

Here is an example of that
https://www.awesomescreenshot.com/video/22776555?key=9d6550414f8193d2c6b320a955169c16

Please add this CSS in the Additional CSS

@media only screen and (max-width: 900px){

.mobile-nav-wrap{
padding: 10px;
position: relative;
}

a#mobile-trigger {
float: none;
text-align: left;
}

#page {
margin-top: 0px;
}
}