An owner may let someone else use their private section (article 5:120(1) BW). The Model Regulations 2017 call that person the occupant (gebruiker): someone who, as a tenant or otherwise, but not as owner or under a limited property right, uses a private section (article 1.1(k)).
The regulations' rules on use, management and maintenance also apply to the occupant; other provisions can be declared applicable to them (article 5:120(2) BW). A provision registered only after the lease was concluded does not apply to the tenant unless they agree; the subdistrict court can decide otherwise at an owner's request (paragraph 3). Something similar applies to rules of use set by the meeting (article 5:128(2) BW).
An occupant is not a member of the VvE and has no voting right. They must, however, give the board access when needed for its tasks (article 5:132 BW).
See also: Private section (privé-gedeelte), House rules (huishoudelijk reglement), Regulations of division (splitsingsreglement), Apartment owner
Legal basis: Boek 5 BW, art. 5:120, 5:128, 5:132, Modelreglement 2017, art. 1.1