In my homebrew setting, not at all...mostly.

Gods worshipped by humans will do little more than leave omens to their priests, and only via methods that are usually not accessible to player clerics.

Most Dwarves practice Ancestor Worship, and Ancestral Spirits can manifest near their icons, but their ability to do more than talk is limited.

There's a group of ancient dragons competing to ascend to godhood, and they are definitely physically present, but aside from a few special gifts from Tiamat/Bahamut, they're just really old powerful dragons.

I've handwaived Divine magic as the result of meditation and purification rituals that anyone can do with extensive training, so even clerical magic isn't necessary proof of a god's existence.