Lviv is the Ukrainian city, respectively, the entire payment is also made in the national Ukrainian currency - hryvnia.
However, taking into account the proximity of the city's location to the border and the fact that it is literally the "window to Europe", the proximity of Poland and a huge number of all sorts of tourists and vacationers, in the city you can face the most all kinds of tourists and their currency. In this regard, in the city without problems, you can find where to exchange money into Ukrainian hryvnia. In case you have fallen into some establishment, without changing the currency, you can try to persuade the staff to accept you for money that is. If the situation is included, it will still be overpayment, compared with the bank's course, but not so much chance to be in a situation where there is money, but nothing is impossible to do with them.
In the daytime, banks and exchange offices are working without any problems. However, for successful exchange, documents confirming the identity may be required.
It is more profitable to change there, where the course is higher, and more often it happens in ordinary exchanger. Exchange best all money immediately, so as not to contact later for searching several times. And the remaining hryvnia spend on souvenirs and delicious coffee.
The city is very developed, and the ATM will not make problems. However, some of the money is still better to take in cash, because ATMs do not always work smoothly. Arriving on large holidays, and getting on the weekend, it is worth providing for cashing money and currency exchange.
And it is also not necessary to remove all the money in an ATM, you can pay the cafe and the bank card.