For posting on Collectibles.Wiki, most smartphone cameras do a good enough job (especially if you follow the rest of the advices on this page)

Consider the background your action figures needs, We mostly shoot on white background (A simple sheet of paper should do the trick)

Place light sources on either side of your model. If you’re serious, invest in daylight temps or in a portable photo station.

Every action figure has a golden angle, a viewpoint that best captures the essence of the model.

Get CLose enough to capture detail without clipping off details around the edges.

Make sure your camera is focused on the right point. If you plan to submit them for viewing online, check them on a computer screen.