Viscose can shrink if you wash it wrong.
Therefore, always check your care label to see the washing instruction before throwing into the machine.

Always hang your viscose and lyocell products up to dry.
Then you avoid the fabric being wrinkled and also store in your wardrobe on a hanger.

Viscose materials do have a tendency to shrink during wash.
Get your product back to the original shape, by ironing while still being damp.