The settings file stores all parameters (and its values) of an Expert Advisor or Indicator in one file. This makes it easier to share settings with others or to store them on your computer for later use.
You can save and load setting inside the Inputs tab of your Expert Advisor or Indicator.
To open the Properties of an Expert Advisor, right click on the chart > Expert Advisors > Properties.
To open the Properties of an Indicator, right click on the chart > Indicators List > Choose indicator > Edit.
By clicking on the Reset button in the right below corner, the EA will use its default settings.