Domains can be renewed by the owner of a domain (the individual who registered the domain), using the regular renewal procedure. Notifications will be sent by email.
In case there are roles assigned to this domain, the 'Admin' and/or the 'Billing' role are also enabled to renew a domain.
Please find out more about 'roles' here.
In case no authorized person is available, the 'Simple Renewal' procedure can also be used.
This allows anyone to renew a domain, but without being able to change any other aspect of the domain.