I noticed that Reallusion offers Realistic Human 100 pack with Crazytalk 8 pipeline. How do I use Realistic Human 100 pack? Is it a software or is it just a pack of pictures? How do I use that pack to create heads for humans in Crazytalk 8?

I saw some tutorials and noticed you can do face fitting in Crazytalk 8 using photos. So what is the connection between Realistic Human 10 and Crazytalk? What software do I use to texture and cutomize those 100 characters that come with Realistic Humans 100 pack? Does Realistic Human 100 comes with character creator? If so does character creator output the face file as .RLHead which we can import into CT8? 

Note: I have never used CT8 or character creator before. So I am totally a beginner with this software and need to make an informed decision prior to purchasing the software and content packs. Thanks for your help.

They are morphs and textures. Think of them as 3D heads that can be applied to CT8 and CC characters. They can also be applied to CC characters that have been sent to iClone as iAvatars.

So basically, they are data.

Have a look at this:
https://www.reallusion.com/contentstore/iClone/pack/Realistic_Human_100/help.aspx

Note that although it says they are for CC and iClone 6, they are fully compatible with CC2 and iC7 as well. And CT8, of course.

Thank you sir for your reply. I just have a quick follow up question. Do you customize the textures and skins of the Realistic Human Heads in Crazytalk? Or is there another software you have to buy to customize the heads? I need to know how to customize the heads before importing them to crazytalk 8. It is my understanding that after you import the head into crazytalk 8, you can apply clothing, hair, accessories to the character and then animate them. I want to know what software is used to customize the head from one of those 100 heads available. Thanks again for your help.

Hopefully some CT8 people will chime in, but You can edit the texture map of the face in an image editor.

The main character customizing program is Character Creator. There you could add wrinkle-maps, change head shape, etc. Character Creator is free when you purchase iClone 6 Pro or iClone 7. 

If you would like a preview of CC, you can download the "Lite" version. It is limited to only 5 character exports, and cannot use additional content packs, but is enough to let you do some great character editing.

https://www.reallusion.com/character-creator/download.html

Thank you again for the links you sent. I will look into this further. I appreciate your help with my questions. For now I am going to hold off on getting CT8 until I know how to use it and what I can do with it. So I will keep watching the forums and training videos!