If you’ve been off sick for 7 days 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. We call this self-certification.
Find out more about sick notes on the NHS website.When do I need a fit note? - NHS (www.nhs.uk)
Charges for fit notes
There is usually no charge for providing a fit note if you are off sick for more than seven days.
Some employers may request a fit note (e.g. from employees who repeatedly take time off sick) even if they are off work for seven days or less. This is a private non-NHS medical certificate.
For sickness of seven days or less, a charge of £20 is payable in order for us to provide a certificate.