I suggest you create a specific email for the role – such as “SecretaryOfSP1234@gmail.com” and use that for general strata matters. It means that when you cease being Secretary, or Chair or Treasurer, you can pass the email address and its password on to your replacement, who will see a history of the ongoing matters for the building. Register this email on the HUB. You can also share the email and its password with other Committee members, and provide its details and password to your strata manager, so if you busy or unavailable, others can step in if required.
As for a phone number, this isn’t absolutely necessary to provide, unless the building pays for a mobile service to be used by the Secretary or Committee (an increasingly common practice). As long as some kind of communication contact is provided, the HUB is serving its purpose.