The position that I recommend for working and meditating is to sit on a cushion of about 10-15 cm high, commonly called zafu, you can also use a yoga brick, on a cushioned mat about 1mt x 1mt commonly called zabuton, or you can also put a folded yoga mat under the cushion.
Sitting cross-legged with each leg facing each other and resting on the ground. Hands on your thighs or left hand on top of the right hand with both palms up and the tips of the thumbs touching gently. Back straight, this is very important! and head aligned. The tip of the tongue behind the upper teeth. Eyes open and relaxed eyelids. This position helps you keep stability, upright but relaxed, so you can stay for long sitting in this way. If you feel sleepy or your mind is very fast you will notice it on your thumbs, in your eyes and in your spine. Try to correct your posture as soon as you notice that it is out of balance.
Find a quiet room or a place where you have no distractions or noise. Sit preferably in front of a white wall, since the objects and designs stimulate the mind and distract us.
Your goal is that your body and mind are still, as relaxed as if asleep, but really awake and alert at a time.
When we spend hours on the computer, sitting in a chair this hurts our body, so it's good if you can adopt the half-lotus posture just described, also for working.
If your knees hurt and you rather sit on a chair, it is important to keep your back very straight.
Another position for both work and to meditate is to stand with a very straight back and head in line. It's good to switch between this position and the half-lotus posture.
Finally there is the savasana pose, which involves lying down on your back on a yoga mat with your arms resting at your sides. You can put a small pillow under your head if it helps you align your spine. This position is excellent for relaxation and meditation, but it is not good to work! You also run the risk of falling asleep, so it is good to use it only when you're stressed or when you have tension in the body.
What posture do you find most comfortable to meditate and work with? How long can you stay in that position without moving?