Is it possible to tattoo to cover vitiligo?

You could but...: Tattooing to achieve normal skin color can be very challenging even for expert tattoo artists. Vitiligo is an autoimmune disease so there is an inherent risk in placing a permanent dye in skin so affected. That said it's your skin & your life. I suggest: choose an artist who has previously done such work. Start with a small inconspicuous area. Wait a few months to see results before doing more.

Difficult: Matching skin color is a hard process if you just want to cover the areas of hypopigmentation these inks tend to oxidize in time and change color so even if they match the color in time that may not be the case

Possible but: it would merely make the area less obvious but would not pass close scrutiny. Also after the ink starts to fade in a few years, you will have to do it again. On the other hand, at the right place, a nice-looking tattoo with darker color ink may mask the vitiligo