Spotlight Search is a really useful feature because it lets you quickly search your entire iPhone. Just swipe down from the center of your screen to bring it up.
Have a lot of apps? Search for the one you need in Spotlight. The results will even show you which folder the app is in.
Need to find an email or message from a contact? Type that person's name into the search field and their contact info and a list of messages and emails will come up.
You can also search Notes, Reminders, Music, and a host of other things. And you can maximize its usefulness by customizing what Spotlight searches and the order it presents the results in. Here's how:
Go to Settings>General>Spotlight Search.
You will see a list of categories that Spotlight searches. A checkmark next to a category indicates that Spotlight will search that category. Tap the category name to check or uncheck.
If you find yourself looking for results in some categories more than others, you can also customize the order Spotlight shows you the search results. Just hold and drag the three horizontal bars next to the category name and move the search category names until they are in the order you prefer.