What's a credit inquiry?
An inquiry refers to a request to look at your credit file, and it generally falls into one of two types.
These are typically inquiries by lenders after you apply for credit. These inquiries will impact your credit score because most credit scoring models look at how recently and how frequently you apply for credit.
These are reviews of your credit file, including reviews of existing accounts by lenders, prescreening inquiries by prospective lenders, and your requests for your annual credit report. These will not change your credit score.