Magic of leaf mould
Whilst they can, and often are, added to the compost heaps they are so valuable it is far better to keep them apart.
A simple but effective way unless you have access to large quantities (lucky you!), is to stuff them into black bin liners, add a handful of activator, tie up the top with twine, punch in a few drainage holes and plate them in some out of the way spot.
It takes anything up to two years to produce really superb, crumbly “Black Gold” that smells so sweetly and is 100% humus.
This will improve your seed beds, potting composts immensely and I also suggest that put a 6” layer in the base when constructing raised beds. Whilst all freshly fallen leaves can be used beech is No1 with oak a close second.