❓What qualities/behaviours should housewife have? Pretty, cute, hardworking, responsible, kind..?
Integrity, honesty, frugality, forthrightness, a willingness to submit but also to speak get mind if I'm being a silly gut, lovely, loveable, witty, a love of reading, competence, a mind to organize, a desire for children, an enthusiastic partner in bed, a love of the outdoors, a desire to grow much of our own food, long time preferences, and probably dislikes shoes.
❓What tasks should she be doing at home?
Whatever she pleases as long as she does her share of things around the house.
❓Should it be wish of woman to become housewife? Or man or both wish?
Both. A marriage is a team effort.
❓Is housewife considered to be housewife if she living in flat? Or it only counts when it is in house, homestead?
I think it would be better to say "homewife" than housewife. If your home is a flat, then that's that. If you live on a farm? What's the harm? Abide in a house? Be a stay at home spouse.