Contributor - maintains packaging specifications and reads everything else. The person who knows what the carton weighs.
Compliance Manager - everything a Contributor can, plus running assessments, computing and submitting declarations, holding registration numbers, and editing jurisdictions, obligations and fee rates. The person whose name is on the filing.
Neither role is granted by default. Assign them under Settings - Users.
That split exists because a declaration is a legal statement. The person weighing cartons should not be able to file one by accident.
Registrations, declarations, assessments, deadlines and packaging specifications belong to a company and are filtered by the usual Odoo record rules.
Reference data - jurisdictions, obligations, rates, materials - is shared. The law is the same whoever is reading it.
Only a Compliance Manager can change it, and an unreadable key is refused at the point of entry rather than stored to confuse somebody later.