can a lady with h4 visa work for places like salesgirl or attendees?

Answer 1

Not legally. The H1b visa gives your husband the right to work in the US, but not you. Working illegally puts both you and your husband at some risk. You can ask DHS for permission to work, but it's hard to say what they'll do. Otherwise, you might consider having a work petition filed for you. But the types of jobs you're talking about wouldn't qualify for an H1b, maybe an H2 though.

Answer 2

Salesgirls and attendees need no visa to work if tolerated by the employers.