When you get a credit card, one thing you should do at once is not to sign, but to find a pen with a suitable signature. The safest way is to use a ballpoint pen and write patiently until the handwriting is dry. In any case, don't use the usual pen or pen. It's not easy to sign with that pen, it's spent at the touch. Even if it is dry, it will still flower when it is wet, and it will be ugly when it is spent. I thought the oil-based pen was ok, but some friends found that the quality of the oil-based pen bought in the market was very poor, and it still cost money to write it on the signature. Before signing, you'd better find a piece of paper and practice signing before signing. If the label is deformed accidentally, it will affect your future use.