How to clean up raised garden bed for winter?

This website sounds easy.

Hi JoJo. My name is Cindy. If you want the plants to come back next Spring, don't do anything with the roots. It's important that the roots are not disturbed. You should cover them for the winter. You can cover them with 3 or 4 inches of mulch, or you can cover them with cardboard. (that's what I do) Place some big rocks on top of the cardboard to hold it in place all winter. I hope this info helps you. Good wishes and happy gardening.

I direct compost over winter and just let it sit. Sometimes I take leaf's and cover the soil and it slowly works in as I direct compost. This just makes the soil better come spring.

>https://www.gardenupgreen.com/2015/05/direct-compost-update.html

Plant a cover crop. Contact your local extension office for suggestions of ground cover for your area. In the spring before planting incorporate it into your soil. This adds nitrogen and other nutrients into your soil naturally.