Edit Full Webtop Text v15.1.4

Found it. Select General Customization, Select the Text option. Find the Webtop profile, select Full Webtop Settings and Webtop Header Message.

It's also possible to change the text with use of javascript. In the Advanced Customization settings, navigate to the webtop and add the code below to the user-webtop.js file. This example may help others when making changes to parts that can't be found in the General Customization settings.

define(["require", "exports", "tslib", "module", "apmui/page/webtop/View"], function (require, exports, tslib_1, module, View_1) {
    "use strict";
    Object.defineProperty(exports, "__esModule", { value: true });
    requirejs.config({
        map: {
            'apmui/master/View': {
                'apmui/page/webtop/View': module.id,
            },
        },
    });
    /* Replacement View component */
    var CustomWebtopView = /** @class */ (function (_super) {
        tslib_1.__extends(CustomWebtopView, _super);
        function CustomWebtopView() {
            return _super !== null && _super.apply(this, arguments) || this;
        }
        CustomWebtopView.prototype.componentDidMount = function () {
            var header = document.getElementsByClassName('apmui-header')[0];
            var span = header.getElementsByTagName("SPAN")[0];
            
            span.style.visibility = 'hidden';
        };
        
        CustomWebtopView.prototype.componentDidUpdate = function () {
 
            var header = document.getElementsByClassName('apmui-header')[0];
            var span = header.getElementsByTagName("SPAN")[0];
            span.innerHTML = "My Cool Company";
            
            span.style.visibility = 'visible';
 
        };
        return CustomWebtopView;
    }(View_1.default));
    exports.default = CustomWebtopView;
});