Knowledge base is a place, where users can find detailed information about your business, products or services you provide.
It can cover everything from technical help documentation to step-by-step guides explaining how things work to frequently asked questions (FAQ).
A knowledge base can be used as a self-service, allowing users to search and find articles by some keywords before contacting your support team. Basically, it saves your support team a lot of time explaining complicated things to users, as articles can be quickly shared with users.
While creating a knowledge base, it's always a good idea to start thinking as a customer — what would one want to know, which keywords would they use to find the required info. Draw a little sketch with all the required categories and sections, and you're ready to start building your database.