Every receiver needs to have a useful frequency display, so you can determine the frequency of a received signal on the set, or you can search for a signal on a known frequency.
On domestic radios and older sets, there are frequency dials on which the operation frequency can be read, modern sets and specially in high-quality „world receivers“ have a digital frequency display.
A digital frequency display is very helpful in tuning a set to a known frequency, in determining the frequency of an unknown signal or identifying a station on a frequency according to a frequency covering plan.
Different technologies are used for digital displays: