The short answer
Follow her lead. Handshakes between people of the same gender are the norm in Morocco; across genders, wait to see whether the other person offers a hand. If she does, shake it. If she doesn't, a nod, a smile and 'salam' are perfectly polite.
In more detail
Greetings matter a great deal in Marrakech, and the right one sets the tone for any conversation. Starting with a question and no greeting feels abrupt, so the 'salam' comes first, then the handshake if one is offered.
Women travellers can apply the same rule in reverse with Moroccan men. Plenty will shake hands; some won't, and that is not meant as rudeness.
Whatever happens with hands, the spoken greeting is what counts: 'salam' or 'salam alaykum' on arrival, and 'bslama' on leaving.
In a shop or a riad, greet everyone, not only the person you shake hands with. A nod and a 'salam' to the woman at the counter or the older man in the doorway includes them without asking anyone to touch hands.
Good to know
- Same gender: shake hands.
- Across genders: wait for a hand to be offered.
- Always greet before asking a question.
- Shake with your right hand.
- Follow the other person's lead every time.
- Say 'bslama' when you leave.