Kanban displays records as cards split into columns by whatever stage they're currently in - like "New inquiry", "Quote sent", "In progress", "Done" for jobs, or "To do", "In progress", "Done" for tasks. Moving a card between columns (typically by dragging it) corresponds to changing the record's status.
The method comes from manufacturing (the Japanese word "kanban" means a visual signal card) and spread into software thanks to how easy it is to read at a glance - you can immediately see where things are getting stuck, without counting or filtering anything.
In a database app, kanban is just one view onto the same data - the very same job record a salesperson sees as a card on the kanban board can be tracked by finance as a row in a table with the same underlying values, just displayed differently.
Related: What is a view, A task manager isn't a system, What a CRM you can edit yourself looks like.