How this is made? I was only told that Illustrator was used. I think it's some kind of template.

I am concerned only about the line work, because the clothes were filled in later. As I have few of those models in different clothes, I see that the line work and faces etc. is used as a template. My friend got it from some digital artwork company, when she wanted to do some clothes modeling examples. now she want's me to remove those clothes, but leave only outline of the model, so I'm guessing how it was made, to replicate the work, because I have 6 models with various clothes textures, that are black and other colour and fades into the line work, so it's hard to remove. I see that it's a template, maybe there was some other software used for those models, don't think they were all drawn by hand, as there are few different outfits, like a coat, a jacket and stuff like that, only shoes and pants and heads (with skin and earing) matches as it would be premade...