Applying for visit visa whose husband already has visa

[Starner]

Hello,
Hope everyone is good. One of friend who got multiple visit visa last year and visited canada already and went back to his home country. His wife now want to visit along with him in future, now question are
1. how should she apply for visa?
2.Should wife apply for visit visa separately?
3. Can husband use his portal for her visa?

Thanks in advance