You can hide the DataGrid header by applying the below styles to DataGrid component.
<style>
.e-grid .e-gridheader .e-columnheader{
display: none;
}
</style>
if you want to hide the header for particular DataGrid, then you can apply the above styles to that DataGrid using the ID (#Grid.e-grid .e-gridheader .e-columnheader) property value.