It is no problem to exchange the most common currencies at any exchange counters in Kathmandu and Pokhara. You can also withdraw cash at an ATM with your international credit card and your personal PIN in various cities and towns of Nepal. You should inform your bank of your travel to Nepal in order to avoid them freezing the account. Debit cards are not advised. Many banks are limiting the withdrawal to 10.000 or 15.000 NPR, however we have good experiences with NABIL bank where you can withdraw up to 35.000 NPR. For any withdrawal the Nepali bank will charge you around 500 NPR for each transaction no matter what amount. Before you go on any trekking tour, have enough cash with you as there won’t be many possibilities to exchange or withdraw money in the mountains.