Tech Requirements for Models and Animation

Hello, everyone
i'm quite new to the unity and would like to ask if there is any tech. requirements for the models.

Basically i mean a document which will include requirements how the model should be created to be imported to the unity (e.g. file format, separated meshes, animations etc.)

So i can give this tech doc to the model designer along with the creative brief, to make sure whatever he designs will fit neatly into the unity.

BR,
Anatoliy