7 days off sick or less
If you're off work sick for 7 days or less, your employer should not ask for medical evidence that you've been ill.
Instead they can ask you to confirm that you've been ill.
You can do this by filling in a form yourself when you return to work. This is called self-certification.
Information and the form for self-certification here
More than 7 days off sick
If you're off work sick for more than 7 days, your employer will usually ask for a fit note (or Statement of Fitness for Work) from a GP, hospital doctor, nurse or pharmacist. Fit notes are sometimes referred to as medical statements or a doctor's note.
If you have already had a fit note and would like an extension, you can:
For more information please visit;
When do I need a fit note? (NHS information)
The fit note: guidance for patients and employees (GOV.uk)