Plumbing - parts and lingo question

The fitting in OP's first photo looks like a standard "swivel" connector fitting like in photo. These are used for connecting a PEX pipe or braided/reinforced flex hose to faucets and toilets and are available in straight or 90 degree and in plastic (RVs) or metal. Swivel fittings have a washer in the end. The flex hose is typically (but not always) connected to a swivel fitting using a clamp like in the 2nd photo. The clamps and tool are readily available all over and the last time I looked are available together with a few clamps for around $30 or so. Can't hurt to have the tool and a few spare clamps in your camper in case you ever need to do a repair on a trip. Do not use a gear type hose clamp, esp. if not using a regulator otherwise you risk the chance of a leak (def. not good for an RV). Another option would be to buy a braided hose like in the 3rd photo with a swivel connector at one end and shark-bite at the other. Also, don't connect to the toilet using a female fitting that would need teflon tape as it will likely leak.