FT8 is a structured, short-message digital mode used in amateur radio. It is available in the WSJT-X software suite and is designed for weak-signal communication.
A typical station combines a transceiver, a computer and an audio or data interface. Audio levels, transmit control, frequency settings and time synchronisation are part of the setup.
Consult the documentation for the installed WSJT-X version when configuring a station or interpreting a decoded message.