Configurable access control will determine who has the access permission to clone a grid in the main grid library; see What is configurable access control?
You can clone a grid from within the grid library, by clicking clone behind the more action button on the grid thumbnail - or - within a selected grid by clicking the clone behind the more action button on the grid action bar.
You can then select to clone “Just grid” (the grid framework with no constituent elements) or “Grid with elements” (the new grid will contain copies of all the original elements – with all element content effectively copied over also).
The cloned (copied) grid is to be found in the same folder as the grid you have cloned from.
For grids cloned from the Method Grid store, the cloned (copied) grid is to be found in your private folder. See How to download a grid from the Method Grid store?