A Bot or software bot is an agent that has been created by the software to mimic human tasks, interpret and execute the tasks for you without needing any form of human-intervention. These bots are programmed to do a certain task or complete a list of tasks all by themselves. There are different types of bots, catering to different situations, like some function when triggered, some are scheduled at a particular time or event, and some work 24*7 round the clock to provide error-free and precise results.
If you are someone who is interested in learning RPA and wish to advance in the domain, then I would suggest you take up the RPA training course from Intellipaat. Also, as a starter watch the following video on Selenium Automation vs Robotic Process Automation.