UK GDPR governs how organisations handle information about identifiable people, such as customers, staff and enquirers. It expects data to be used fairly and lawfully, kept only as long as needed, held securely, and used for clear purposes. People also have rights, including to see the data held about them.
For a business, that means knowing what personal data you hold, where it lives and why. Systems that keep records in one place, control who can see them and keep a log of changes make that far easier to demonstrate. This is general information, not legal advice; for your own situation, speak to a qualified adviser.