When applying, the credit card provider calculates your credit card limit based on your personal data, income, credit score (SCHUFA), and other factors. In the beginning, this limit can be low. You have different options to increase it:
Top-up: Some banks (e.g., Barclays) set up a dedicated account and connect it to your credit card. Hence, you can use it like a prepaid card and transfer money there. Your credit limit automatically increases according to the transfered amount .
Early repayment: To reset your credit limit, you can repay your debt via a manual transfer ahead of time.
Request for extension: You can contact customer service and request an extension. It works best after some months of frequent use and reliable repayments.