Whenever your credit report is accessed a record is made into your credit report. This record is called an enquiry. There are two kinds of enquiries, soft enquiry and hard enquiry. Depending upon which type of an enquiry is present on your credit report it may or may not have an impact on your credit score. While a person with a good credit history should not get worried about the impact of enquiries on the credit score because they are mostly temporary, it is still one of the factors that is considered while calculating the credit score.
When a creditor accesses your credit report owing to the application that you have made for a loan or credit than such an enquiry is called and hard enquiry. A hard enquiry has an effect on the credit score. The amount of the effect will depend on the rest of the history present on your credit report.
Other enquiries made by people that are related to non-credit issues such as potential employers, landlords etc are call soft enquiries and do not affect your credit score at all. In fact soft enquiries are not shown to the lenders in their copy of the credit report. They are only shown in your personal copy of the credit report. When you access your own credit report that is also recorded as a soft enquiry which means that you can access your own credit report as any number of times without any worries of impacting your credit score whatsoever.
Sometimes existing lenders access and existing customers credit report for the purpose of updating and making new offers for lower interest rate or enhanced credit limit. These are also shown only to you and have no impact on the credit score. Similarly arrangements with third parties such as credit monitoring service and credit card companies are also usually structured so that the enquiries made by them are treated as soft enquiries.
So if a third party offers a service where they access your credit report and score to share it with you it will generally be counted as a soft enquiry and will not have an impact on your credit score. Many of the credit monitoring services work on this principle. Your own credit card company may offer to share your credit score with you as a form of additional service had to provide. Before accepting you should however clarify as to whether or not a hard enquiry will be made on your credit report or not.