The short answer is it depends. If you have back pains while seated probably a lying down meditation will be more comfortable for you. Comfort is important while meditating, especially as a beginner, as it can be very distracting. If you are at work in between meetings a seated position might be more appropriate.
Some people meditate lying down while others seated…on a chair or on the floor with legs in lotus position. Some close their eyes, others keep them open…
In most types of meditation, the body needs to be stable and as immobile as possible. It should be noted that it is also possible to meditate while doing repetitive movements such as gardening, eating, chanting, signing, walking or dancing.
The great thing about meditation is that we can do it pretty much anywhere. (Please don’t try while driving a car).