For shower enclosures and doors that have a pivot function, like a normal door, you can often choose between a left or right-hand opening.
Left Hand
The handle is on the right, allowing the door to open to the left when you pull this towards you.
Please find an example of an enclosure of this orientation below:
https://www.victorianplumbing.co.uk/apollo-frameless-hinged-door-rectangular-enclosure-l-h-opening
Right Hand
The handle is on the left, allowing the door to open to the right when you pull this towards you.
Please find an example of an enclosure of this orientation below:
https://www.victorianplumbing.co.uk/apollo-frameless-hinged-door-rectangular-enclosure-r-h-opening