GP Practices are not able to record patient opt out preferences.
To opt out you will need to register with the National Data Opt Out service. You can record your choice via the NHS website, or by phone ( NHS Digital Contact Centre: 0300 3035678) or post.
Details are available on the website: https://www.nhs.uk/your-nhs-data-matters
Your individual care will not be affected by your opt out.