Fingerhut Credit Card reports to the three major credit bureaus once a month, typically at the same time as the statement closing date. So, if your billing cycle ends on the 15th of every month, the issuer will report information on your credit card balance on or around that date.
The information reported to credit bureaus should usually appear on your credit report as soon as it's received. However, it can take up to two months (or billing cycles)...