I found that mixing shredded paper with leaves prevents leaves from matting down, and also greatly increases numbers of red worms in the pile. The result decomposes much faster than leaf mold. I aim for ~20% paper and mix it in as thoroughly as I can, aiming to see some paper in every handful of stuff I can pull from the pile.
Of course, the resulting mix is very 'brown' and would decompose faster with some 'greens' mixed in. A handful or two of urea mixed in occasionally as you make the pile will get it to heat up very nicely and speed decomposition. Urea does not seem to affect worm populations adversely.

Toss them in a vermicompost bin! :D My worms LOVE cardboard!

Leaves have a C:N ratio ranging between 40:1 to 80:1, depending on age, while paper can have a C:N ratio of around 170:1. Newly fallen leaves will have a ratio close to the optimal 30:1 for composting although as they age they will need additional Nitrogen in the mix to be digested, even though piles of leaves will, eventually, be turned into leaf mold.
Wet paper tends to stick together, make paper mache, which can limit the amount of air available to the digesters so something that would prevent paper from matting is necessary. I've not experienced shredded leaves matting anything like unshredded leaves or paper will.

I have been shredding ALL our household waste paper (bills, junk mail, newspaper, phone books, magazines, packaging, boxes, sacks, napkins, TP rolls, etc, etc, etc......) with a contraption I built as an "attachment" to my mulching lawn mower. As I am shredding, I have a chute blowing it into one of my compost bins. This fills up and I wet it down so it won't blow around. Then as I need carbon materials (I don't have any trees around to get leaves) I simply fork in the shredded paper material and mix it with the lawn clippings and other greens. It breaks down just as quickly as the other organic materials and creates a rich compost that has helped produce my last 3 years of amazing raised bed harvest of delicious veggies and beautiful flowers. No waste going to the landfill and I don't have to buy commercial fertilizer nor soil addatives.

The best option is to recycle these items if it is available to you and it is material that is recyclable. If recycling isn't available I've found it's great in a compost pile or worm bin or simply worked into the soil to hold more water. Large peices of paper or cardboard make great weed barriers if laid on the ground and covered with mulch. Pizza boxes work well for this.

I run virtually all of my paper type wastes (only the glossy paper inserts and envelopes with plastic windows go to the recycle people) through my worm bins. The resulting product is great for my garden