Add “Menu” text to hamburger icon (mobile menu icon)

I’ve taken over this website from another builder. The customer has asked for many changes one of which being able to add “Menu” under the mobile icon because some of his older customers doesn’t know to click on the dashes to see menu.

Please give me the code to put in the additional css section of the customize section.

Thanks.

The page I need help with: [log in to see the link]