To self-certify a sick note, you can follow these guidelines:
Employees can self-certify for up to 7 days without needing to provide a medical note to their employer.
After 7 days, a fit note from a registered healthcare professional is required.
Many employers may require you to complete a self-certification form (often referred to as SC2). If your employer does not have their own form, you can download one from the HMRC website.
Self-certification allows employees to confirm their sick leave without needing to see a doctor.
For more detailed information, you can refer to the official government guidance on sick leave.