Why do some peoples characters look all white/like they havent loaded?

[xX_JOLT_Xx]

Do I need marking packs? If so, where can I find those?

[Kerriki]

Moving this to game help

Yup! -- Some users may appear blank white (or a "marshmallow" as commonly called) simply because they're using markings you don't have installed. People tend to use the legendary markings pack, and I don't happen to have a download on hand but I'm sure a helpful floof will come along and provide you one very soon c:

[l3irdie]

Hey floof!

This is the marking pack you're looking for, just get through Adfly (wait for it to let you skip the ad),
https://www.mediafire.com/file/67rf541rkh7051i/Legendary_Markings_v4.1.zip/file

and then go to;
C:\FeralHeart and replace the marking.cfg (it's a text file)

then you have your marking images, go put those in;

C:\FeralHeart\media\textures\markings

should be all set!