My website Menu button is not showing on certain pages on mobile

I’ve been designing my first site for a while now and I’ve recently discovered the menu button at the top of the ‘Contact’ page and also all my ‘Destination’ pages doesn’t seem to show on mobile. By using word press theme we can add the menu button and page button is shown
here is my site @somefins
I’ve tried to search for a solution and used a few different CSS codes and want to know about the solution.