Newspaper works but it degrades over time and will also become torn and looks unsightly. It is good in small places for keeping weeds down, but putting any type of "weed fabric" under organic mulch is a total waste of time and money. The weeds grow in the mulch - it's organic and weeds will grow in it. It honestly serves no purpose other than $$ in the pocket of the person installing it (if you have a professional landscaper doing the work) and the company who makes the weed fabric.

Your best bet for weed control is an integrated weed control management program. In the spring, pre-emergent application, either granular or liquid, mechanical weed removal (pulling), and occasional organic/herbicide application as required.

You can use grass clippings in large areas to control weed growth such as in between the rows in your garden if you mow your lawn and bag the clippings. Empty the bags on the ground between the rows and you will have less weeds in your garden area.