We do recommend you bring some soles with you before landing in Peru or change some at Lima airport if you have time before your connecting flight. Lima airport has both ATM machines that accept international cards, and money exchange shops.
There is a Scotia bank, BCP, and BBVA banks with ATMs in Moyobamba that accept most foreign debit and credit cards, from which it’s possible to withdraw and soles and US$ at the ATMs. It is generally simple to withdraw money in Peru with foreign bank cards.