Credit card and ATM facilities are limited in the Everest region, especially in remote villages along the trekking route. It's advisable to carry enough Nepalese Rupees in cash to cover your expenses during the trek, including meals and souvenirs. In Kathmandu, you'll find more banking options to withdraw or exchange currency before starting the trek. Banks and ATMs are also available in Namche and in Lukla during Everest view trip but it is every time now sure to have it in operation.