Hello @1111
if you have currently selected element then you can refer below code
var modeling = bpmnModeler.get('modeling');
modeling.updateProperties(selectedElement, ,{name: 'mmmm'});
if you don’t have selected element then first you need to get the selected element from elementRegestry
var selectedElement= bpmnModeler.get('selection').get();
for more help you can refer this.