The likely reason as to why you are not able to see the Information Protection option in your Microsoft Purview portal, it may be because your account doesn't have the necessary permissions to access this feature. Kindly check with your administrator to see if they can grant you access.
As for your second question, you can log in to the Microsoft Purview portal using your user ID and password if your account has been granted access to the portal. Kindly look at the Microsoft Purview documentation to learn about the diffrent portals available and how to access them.