Add custom text to menu

There is another alt way to do this with CSS3. You would add a link to the WP Menu as normal but make the Location either javascript:void(0); or # so it doesn’t go anywhere (I would say the javascript... is the better way to prevent anchor link from firing).

Then in your style.css or CSS doc you can get target those links via the href like

header .nav li a[href="#"], header .nav li a[href="#"]:hover,
header .nav li a[href="javascript:void(0);"],
header .nav li a[href="javascript:void(0);"]:hover {
    text-decoration:none !important;
    cursor: text !important
}

Reference: https://css-tricks.com/almanac/selectors/a/attribute/

Your selectors may be different