#1. Add this code to Custom CSS box and click Save

/* burger icon to Menu */
.burger-box:after {
    content: "MENU";
    width: 60px;
    height: 40px;
    display: block;
    color: #000;
    font-size: 20px;
    font-weight: bold;
    visibility: visible;
    margin-top: auto !important;
    margin-bottom: auto !important
}

.burger-box div {
    display: none
}

#2. You will have a result like this