Every time Apple gives the iPhone an operating system (OS) update, several features and updates are not as prominently featured as others or are a little difficult to find, thus earning the label "hidden." The iOS 11 is no exception.

Of course, fans also get a kick out of discovering for themselves what each new iOS' hidden features are. For the more excited of users, here is the breakdown of the most useful but lesser known iOS 11 hidden features.

Volume slider

Understandably, smaller updates get less attention. One such update is the volume slider. It used to be that whenever users adjusted the volume on their iPhones, a graphic would appear in the middle of the screen to indicate volume level. Now, that graphic has been reduced to a drastically smaller version and is tucked away in the upper right corner of the phone's screen.

Email drawings

Users can now also insert drawings into emails. When writing an email, users need only to long-press on the screen and wait for the pop-up that includes the option "Insert Drawing."

Drag and drop words

Drawings are not the only updates that make email writing easier. Users can now also drag and drop words within the same application. iPhone users only have to highlight a word or a group of words and then press on the selected text to drag and drop it into another location.

Emergency SOS

Sometimes, there is no time to send a text message, even if there is a drag and drop option. iOS 11 now integrates an Emergency SOS feature, which allows users to have their phones dial local authorities or specific contacts once the power button is pressed five times.

Depending on user preferences in Settings > Emergency SOS, the phone will either automatically push the call or wait for user confirmation.

Shut Down option

For other kinds of emergencies, the update also includes a new Shut Down option in the settings app, in case the hardware power button malfunctions.

To turn the phone back on without using the power button, users need only plug their phone into a charging cable, because iOS now automatically boots phones when plugged in.

iOS 11 has been available for download since Sept. 19. Some of its more prominently advertised features include augmented reality capability, a redesigned App Store and major updates to the Photos and Camera apps.