After the advent of radio, came the realization that as the solar cycle reached its peak, radio communication with distant stations became easier. Of course during the declining years, communications become poor, if not impossible, on some bands. The purpose is to confirm that two way communication was made between the two stations. These cards contain information about the operator, such as name, call sign, location, etc. As well as information about the contact, band , mode, time of day , date .
Most hams have their own personal cards printed by professional printers.
Some cards are highly sought after, hams will travel to remote islands or countries which have little or no amateur radio activity , then offer QSL cards to everyone who contacts them. QSL cards are a fun way of keeping track of all the different countries or places one has talked to. They are also required for many of the awards that are offered hams. Just about every mode of communication available today is used by amateurs. All forms of digital communication are used as well, computers have become a communication tool used by most of the hams today.