This is your choice. Me, I meditate standing on my bed and I think is good. But as meditation videos say, 《you can practice meditation sitting on a comfortable chair or lying down》. I hope my answer helps you !
Lying down is a very relaxing way to meditate. You can mediate in various poses. There is no one right way to do it. The main thing is finding how to relax and focus on the breathe or whatever intentions/mamtras you want to focus on. I haven't done long meditations in standing poses but if it feels right try it. I'd just be careful of surroundings if doing eyes closed, in case you fall. I've also done mindful meditation walks, I prefer to do that barefoot if possible.
Bette to take a comfortable sitting position (with straight back) or laying down (perfect for pre-sleep practice) , it depends what’s the purpose.