From kalilinuxtutorials.com
BetterBackdoor is a backdoor is a tool used to gain remote access to a machine. Typically, backdoor utilities such as NetCat have 2 main functions: to pipe remote input into cmd or bash and output the response.
This is useful, but it is also limited. BetterBackdoor overcomes these limitations by including the ability to inject keystrokes, get screenshots, transfer files, and many other tasks.