Filtering is a quick and easy way to find and work with a subset of your spreadsheet data while hiding all the rest. Unlike sorting, filtering does not reorder your data; it just temporarily hides the rows you don’t want to see.
Before turning on AutoFilter:
When you use the AutoFilter command, arrows appear to the right of the column labels in the filtered range.
After turning on AutoFilter:
Selecting an item from this drop-down list will automatically filter your list so that only rows containing that value are displayed. You can further filter your data by using selections from more than one column’s drop-down list.
The row numbers for the ones that remain visible turn blue. The drop-down arrow for column(s) that have been used as a filter will also be blue.
Learn more about AutoFilters
This is a VERY handy trick to have in your arsenal and can be a huge time saver if you work with large spreadsheets.
The following links provide more details about working with AutoFilters.