The answer to 'difference between faucet installation' is that there are two main types of faucet installation: deck-mounted and wall-mounted. Deck-mounted faucets are installed directly into the sink or countertop, while wall-mounted faucets are installed directly into the wall behind the sink.
Deck-mounted faucets are generally easier to install and more common in residential settings. They require less plumbing work and can be replaced more easily. Wall-mounted faucets offer a more modern, minimalist look but require more complex plumbing and wall preparation. The choice between the two depends on the homeowner's style preferences, existing plumbing, and DIY skill level.