Filters let you hide items in your list, showing only those items that fit the criteria you've decided on. For instance, you might want to filter your To-Do list so that only unfinished items are visible.

How to Filter Lists 

The simplest way to understand this is to give it a try. Follow these instructions to filter a list:

You can filter a list on multiple columns if you like. You might see items in gray. These are items that don't contain the filter information, but are parents of an item that do contain the information.

Portal Lists and Filters

Some of the portal lists include buttons for specialized filters, designed to help you to easily multi-filter Portal Lists to make them easier to use for their dedicated task.