If the Supplier is provided directly with the Supplier Registration form, the Supplier will receive a couple of emails from MeRLIN.
The first email will mark a copy to the Buyer and the second email will have the password creation link which will only be sent to the Supplier.
The second email, the password creation email will look like the one shown below:
As you click on the Link, you will be taken to the password creation page of MeRLIN. You can create a password and confirm it. Once the password has been set, you can use the email id and the password to log in to the MeRLIN Supplier Portal.