One one hand, a credit card can impact your credit score negatively, yet on the other it can impact your credit score in a positive manner.
Each time you apply for a credit card, it will be recorded on your credit file. If you apply for a credit card and are rejected, this will leave a negative mark on your credit score. Importantly, if you miss repayments, your credit score will also suffer.
If you make regular payments and are responsible with the use of your credit card, this can raise your credit score. In essence, it all comes down to how much you tap or swipe your card and make repayments to pay off accumulated debt.