I use Photoshop 2021 and according to YouTube when I click on Window, the dropdown should show a 'properties' selection. This is not showing, any idea why this might be. On comparison with the YT video, I have a lot fewer options? TIA
You need to be in expert mode.
The Window > Properties command and Sky Replacement occurs only in the full Photoshop, not in Photoshop Elements. There is a Sky Replacement feature in Photoshop Elements Guided mode > Special Edits > Perfect Landscape.
What are you trying to do in the Properties panel which, as Walter says, is only available in Photoshop CC? Most of the information and tools available in the Properties panel is available elsewhere in Elements.