greetings,
how can I attach mask to a character and animate its movement with jaw motion. I attached it to the jaw bone in CC3 but it moves up and down. How can I attach some part of the mask to the nose so it stays there. Thanks. 

You can try to make it a cloth. It will then conform to the face shape.
In CC3 create an accessory from a prop and then transfer the skin weights.
But i'm not sure if the results are exactly what you want...

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Thanks. But after transferring skin weight and converting it to accessory the add to custom (+) is grayed out.  

Thanks. But after transferring skin weight and converting it to accessory the add to custom (+) is grayed out.                                 

You should not convert it to accessory. That is effectively wipes out all transfers and assign 100% influence to the head.
You should keep it as cloth. After transferring skin weights, custom skin weights assignment is necessary.

1. Assign 100% weight for all mask vertices to Head bone (the value of 1).
2. Paint mask for the JawRoot bone approximately as shown on screenshot.
This would allow bottom part of the mask to move as person speaks up.

Thank you very much it is working but with the cloth breaking up and sometimes the face protrudes and shows up. I guess I have to work with the mask geometry itself. Thank you again.