Respond to texts without unlocking your phone.
You can respond to texts directly from your lock screen by pulling down on the notification drawer and swiping over to the left on the text notification. You'll see a "Reply" option, and tapping it will let you type a response without having to unlock your iPhone.
Respond to texts while you're in an app.
If you're in an app, you can swipe down from the top and access the notification drawer to answer a text the same way you would on the lock screen.
See which apps drain the most battery.
Want to know why your iPhone battery is draining faster than usual? Head over to Settings >General >Usage>Battery Usage. This will tell you which apps are occupying the most battery power.
View every photo someone has texted you, and vice versa
There's an easy way to view every photo and video you've sent someone. Just open the messaging thread in the "Messages" app and press the "Details" button in the upper right corner.
Send audio and video messages that self-destruct.
You can send audio snippets and video messages that expire after two minutes. If you head to Settings>Messages and scroll to the bottom, you'll notice a section for audio and video messages. You can choose to let them expire after two minutes or never.
Share your current location with a friend.
If you don't feel like explaining where you are, you can simply send your location to another person via text message. Just tap the "Details" button in the upper right corner of your message thread and select "Send My Location."
Let your friends track where you go.
If you want your friends or a family member to be able to track you as you move, you can complete the same steps mentioned in the previous slide and choose the "Share My Location" instead of "Send My Location." You can choose to share your location for one hour, until the end of the day, or indefinitely.
Mute text messages.
You can mute text message notifications for individual contacts and conversations. Just head over to your messaging thread and switch the "Do Not Disturb."
Leave a group conversation.
Group texts can be effective for reaching many people at once, but also annoying. If you want to leave a group conversation, simply tap the "Details" button in the upper right corner of the group conversation and select "Leave Conversation."
Name a group conversation.
If you frequently chat with the same group or are talking with multiple people about a particular topic, naming a group conversation can be helpful. To do this, head over to "Details" in the message thread and fill in the "Group Name" field with an appropriate title.
Multitask within emails.
If you're in the middle of an email, you don't need to trash it to return to your inbox and browse other messages. As you're composing an email, simply tap the top of the message where it says either "New Message" or the subject and drag it down to the bottom of the screen. This will push the message to the bottom so you can look at other emails. When you want to return, simply tap the email to keep editing it.
Forward text messages to other contacts.
You can forward text messages to other contacts the same way you would an email. Just double tap the message you want to forward, press the "More" option that appears next to the text, and that specific sentence, word, or phrase will appear copy and pasted into a new message. Fill in the "To" field at the top to forward that message to someone else.
Use Siri hands-free.
You don't always have to hold down the home button to launch Siri. If you're iPhone is plugged in, you can say the phrase "Hey Siri"to launch Apple's virtual assistant. Just head over to Settings>General>Siri and turn on Enable Hey Siri first.
Have Siri read anything.
You can enable Siri to read articles on websites, books, text messages, and more thanks to one of the iPhone's lesser-known accessibility features. Head over to Settings>General>Accessibility>Speech. Then turn on Speak Screen and Speak Selection. Now, when you swipe down from from the top of the screen with two fingers, Siri will dictate the content of whatever is on the screen.
Tell Siri how to pronounce names.
You can also teach Siri how to pronounce names. First, launch Siri and ask her to say the name in question (i.e. if it's your name, ask "What's my name?"). When she answers, tell her that she's not pronouncing it correctly. Make sure you use her pronunciation so that she knows which word you're talking about. Siri should then ask you how to correctly pronounce the name. Once you do, she will present three ways to pronounce the name. Choose the correct one, and Siri will remember it.
Control your iPhone by simply moving your head.
This is another feature buried in the Accessibility section. Navigate to Settings>General>Accessibility and then scroll down to the Interaction subhead and tap "Switch Control." Tap "Switches" and "Add New Switch." Select "Camera" and choose "Left Head Movement" or "Right Head Movement." Then pick an action under the "System" menu, which essentially tells you what task your head movement will trigger. I chose Siri, so each time I tilt my head to the left it automatically launches Siri.
See everywhere you've been.
You're iPhone tracks each place you've been, and there's a way to find it by digging into your phone's settings. Press the Settings icon and head to Privacy>Location Services>System Services. Then, scroll to the bottom and select "Frequent Locations" and look at the History section.
Save battery by putting your phone in grayscale mode.
If you're running low on juice and just need basic functionality from your iPhone, try switching it to grayscale mode to save power. Just head to Settings>General>Accessibility and tap "Grayscale."
Tap the home button twice to move app icons and other content toward the bottom of the screen (iPhone 6 Plus only)
If you're using the iPhone 6 or iPhone 6 Plus with one hand, you can double tap the home button to schootch content down toward the bottom of the screen. Apple calls this "Reachability Mode." Remember to tap the home button, don't press it or else it'll launch the app switcher.
Access emergency medical information directly from the lock screen.
If you set up a Medical ID in the Health app that comes with iOS 8, you can access medical information without having to unlock your iPhone. Tap the "Emergency" button that appears with the keypad for entering your passcode and you'll see the Medical ID button on the lower left corner.
