Which is better generally a desktop or a laptop?

Apples and oranges. The question is "better for whom".
Desktops have lower cost, tend to have higher processing power on average and the upper end (gaming or super), especially disk space, part configuration and maintenance is a possibility. However, possess low portability, maintenance is a bother, sticking with one for too long will produce overheating & noise pollution beside unpredictable (and potentially catastrophic) failures, back in my day they didn't possess basic important hardware (builtin network adapter, bluetooth, input / output devices obviously).
On the other hand, in laptops if you get some faulty parts, ad hoc drivers or bad tech support, you're quite screwed as well.
Overall, a casual user with no heavy duty necessities should stick with a mediocre laptop for themselves, most companies prefer a set of standardised desktops to simplify upkeep and upgrades (eg OS compatibility).