Is there a generic term for words "subscription" and "account"?
Solution 1:
Good that you provide a context. Anywhere with computer accounts there can be many levels of accounts depending on permissions and features available. These enforce levels of security. Each product names these as they will both to keep distinctions and sometimes to show that their product describes them better.
An Account meaning a log in identity is the most standard way to designate this. Further description adds permissions based on the need of the user to modify their own and others data. Admin and Master accounts describe administrators with increasing rights on up to the most empowered DBA.
Subscriptions would be a characteristic of what the account is used to access, which data feeds etc.
For a single word you might go with the most basic of log in or log in ID.