It means "How about...?" コーヒーはいかがですか？ Proposal: Would you like coffee? その後いかが(お過ごし)ですか？ Question: How have you been? Just いかがですか means several things but mostly; How do you like this or how do you think?

It means 'how is..?' 具合(ぐあい)はいかがですか How's your condition?