I saw few voobly mods in steam, but is it possible to copy steam mods into voobly?

The mod centers are not compatible with each other, you still have to adapt all mods so the are working with AOC/AOK.

Adaptability is a deeper concept! How could we be able to make steam mod adapted to voobly?

That depends on the mod. You must make it compatible to the original AOK/AOC, e. g. converting graphics and creating the required SLPs.