Go to the DigiD website. click on 'More information' under the heading Authorize. Then click 'Request authorization'.
To be authorized, click 'Become authorized'.

You can also go directly to the DigiD Authorization website. This is Machtigen.DigiD.nl.

In the list you now see you can search for the healthcare institution for which you want to be authorized.
If this is not listed, it is best to contact the healthcare institution to inquire whether it is possible to be authorized.
They can then give you more information about how this works.

Select the healthcare provider and click 'Next one'. Then click 'Log in with DigiD'. Log in now with your own DigiD.
Then enter the details of the person for whom you want to be authorized. Then click 'Next one' and enter the start and end dates.
You will now see a summary of the data. If everything is correct, click on 'To confirm'.
An authorization has now been requested.

The person for whom you have requested the authorization will receive a letter with a code. You need this code to activate the authorization.
To do this you go Machtigen.Digid.nl and clicks 'Activate authorization'.
Enter the authorization code and the Citizen Service Number of the person for whom you are being authorized.

You will receive the message 'The authorization has been activated' and activation was successful.
You can now log in as a representative for someone else.