Can the panel be in upside down? And how far away from the sink or hot water heater does the panel have to be? I'm looking for a new location for panel. Thank you tony

As long as the main breaker moves side to side, as opposed to up/down, there is no "upside down". Main breaker on top or bottom is fine.

There is no separation from a sink or water heater. As long as the 30" wide working space is maintained. And so you know, the panel does not need to be centered in the 30" wide space. The panel can literally be placed right next to a sink ro water heater, as long as thee is 30" clear wher the panel is mounted.
The panel just needs to be placed somewhere in a 30" wide clear space.