The functions of a 0-yuan credit card include: establishing credit history and offering preferential activities.

1. Establish a credit record: By opening a 0-yuan credit card, you can establish your own credit record, which is very helpful if you want to apply for a higher credit card or loan in the future.

2. Preferential activities: Banks will provide special preferential activities for 0 yuan credit card holders, such as providing certain goods or services for free, or enjoying lower interest rates, etc.