The process of applying for an education loan and issuing a demand letter in itself does not directly impact your credit score. However, how you manage the loan (timely repayments, for instance) post-disbursement can significantly affect your credit score. Maintaining a good repayment history will positively impact your credit score, while delays or defaults can negatively affect it. It's essential to understand the terms outlined in your demand letter and adhere to them to manage your loan responsibly.