What do you mean by wood color? If you mean stain it to a lighter wood like bamboo, oak, or pine, then no. You can't. You'd have to laminate it with a veneer. If you mean paint the shelf a solid color, then you'd just need primer and paint.

You're gonna be painting this. So it's gonna be a single shade of color. You'll be losing any "wood" look.

Chalk paint in a lighter color with a darker way overlay.

Prep wood, primer, and paint. You may need a couple of coats.

Yeah a hard no on bleach. The only way to make that lighter would be to paint it. It is sawdust pressed together with binders and has a grain texture molded in. It will take several coats of primer and paint in most cases depending on what the outer sealant they used at the factory.

Bleach would just harm the wood and you'd get no color change.

You can repaint with a faux wood grain look. There are tutorials on YouTube on different ways to do it, from using wood grain rocker/roller/comb tools, to simply using different paint colors layered with directional brush strokes. It isn't that hard, but you'd need a little patience, space, and dry time. If that seems like a lot, you could always cover with a lighter toned wood-patterned adhesive laminate (contact paper/shelf liner).

That's just a thin piece of veneer over particle board. All you can really do is paint over it. Its not gonna look like wood unless you do some kinda faux finish. Also depending on what the veneer is finished with it might be hard to get paint to stick unless you get the right kind. Sanding it and restaining it isn't an option since it's not evan 1/16" thick. Bleach isn't gonna do anything at all.

I would just clean it real good and and easiest would be to spray it with whatever paint color you want.