A limited company is required to complete annually a Companies House Confirmation Statement.  There is a charge for this via Companies House, see costs from 2024 Changes to Companies House fees – Changes to UK company

Some companies charge a fee to process this for you.  You may receive a reminder letter or email to complete via a 3^rd party company.  These companies are not part of Companies House, and you should be mindful of the additional higher costs that they charge, which will impact upon your business costs.

Ensure you review the most up to date information from Companies House, you can also sign up for email reminders  through their website

Registering for email reminders from Companies House – GOV.UK 

File your confirmation statement (annual return) with Companies House – GOV.UK

Changes to Companies House fees – Changes to UK company law