You do not need to show any evidence if you are exempt from wearing a face masks in a shop
If you have an age, health or disability reason for not wearing a face covering:
you do not routinely need to show any written evidence of this
you do not need show an exemption card
This means that you do not need to seek advice or request a letter from a medical professional about your reason for not wearing a face covering.
However, some people may feel more comfortable showing something that says they do not have to wear a face covering. This could be in the form of an exemption card, badge or even a home-made sign.
Carrying an exemption card or badge is a personal choice and is not required by law.