Parameters are a fancy term to me for a variable that you can change the value of any time you wish. Parameters on a report allow you to change what data you are actually loading and looking at.
If you set up a parameter on a date column you can filter what dates from your data source actually get loaded.
If you decide to set a parameter on a geographical column like state or city, you get to decide what geographical data actually gets loaded.
If you set a parameter on a data source you get to decide what source you are pulling your data from.
You might be thinking, can’t I just do all of that in the Power Query editor using filters on a column. You are correct in your thinking, but I need you to think beyond the desktop application and think about what happens when you publish out to the service. I need you to think about what your end-user needs to decipher what data they are going to look at.
If I have tickled your interest, in what parameters can do then take a look at my DEMO VIDEO for a basic example of how parameters can help you develop your Power BI reports. Stay tuned for more advanced examples of incorporating parameters.