Water valve replacement

Turn off the water first. :B

It all depends on the brand and model toilet. Some are very simple and others more difficult.

Sharkbite fittings work great on PEX if needed.

Bobbo wrote:
Turn off the water first. :B

:B While we are taking baby steps, you might want to flush the toilet to rid the line of residual water.

Have a rag handy to block the hole, once you remove the bowl.
*If you are also replacing the blade seal, i would pour some water into the bowl before you remount it. See if the seal is holding .
•If you’re replacing the water valve on the back of the toilet, once you have reinstalled the water line, pressurize the water system to make sure the valve doesn’t leak, then you bolt it down.
* use a new rubber seal at the floor flange.

Good advice above. I replaced a water valve once due to low flow. When the new valve didn't help I took a small screwdriver and poked it in the hole where the water comes out to find it was clogged with minerals in the water. KISS.