Hi Carol
There are a few ATMs in Havana but not as many as you would expect in other major cities. If you can find one, you should be able to use a Visa Debit card but many travellers say it's not possible to use Maestro/Cirrus. Personally I would take plenty of cash with me and change it to CUCs on arrival in Cuba. By all means take your cards too but I wouldn't rely on them. As always, let your bank know about your plans before you go.
Kind regards,
Olly, your editor