Searching is Google’s best attribute and that applies to searching in GMail as well. Many are used to other email applications that allow you to search by sender, date, attachments, etc. In GMail, those search features are hidden but easily accessible. Simply click on the tiny triangle at the end of the search bar in GMail – see image below.
Once clicked, you will be able to search by a number of different criteria and, if you find a particular criteria useful, you can create a filter based on that criteria.
