Hedgehogs do eat slugs and snails but only if they are very hungry. They carry lungworm which can kill hogs so are not at all good for them. They make up about 5% of their natural diet but are not their first choice!
Hogs eat insects and bugs so like gardens with lots of shrubs and plants that attract insects. A general wildlife garden, I suppose, or cottage type garden. Also areas left a bit wild and not too tidy .... Old log piles, nettles, wild flowers, long grass etc.
No slug pellets or rat poison that is accessible.
Ponds should have ramps or shallow edges so that hogs can get out.
Ramps in cattle grids .... They often get stuck down there and starve to death if not found and rescued.
Garden netting is very dangerous. They get tangled in it and die there or from infected wounds as they try to escape.
Strimmers cause horrific injuries. Check before you strim.
In fact, people say that sheep look for ways to die, but hedgehogs seem to be the ones with a death wish!