Afsal, the menus are added in the sidebar Add new widget by the plugins, the order depends on the order you activated your plugins on the website

Adding a new item to the sidebar Add new widget is considered as a custom code modification. 

So do i have to populate the whole menus by new codes? please explain

To add a new menu item, you need to develop a plugin 

You can check Groups plugin init.php file to see how it works

I need to change the positions of the systems menu and some sub menus to main menu. 

The menu constructs from the available system plugins and other plugins?

What do you mean by sub menus? 

Main menu items positions can be changed in the Pages section in the admin panel, by dragging and dropping the items to the desired position. 

Yes, the menu items come from the plugins

Hi,

I jus need to re-arrange admin menu, not front end menu.

Topic was moved from General Questions.

Did myself