Just a few hours ago, Apple announced that the company sold more than 13 million iPhone 6S series phones in just three days. The company apparently sold 3 million units more than last year.

With so many iPhone 6S series devices out in the hands of millions of users across the world, there will be some who are still unaware of the Apple device's marquee feature 3D Touch.

For the uninitiated, 3D Touch is the key factor differentiating between the models of 2014 and 2015. 3D Touch Display is an advanced version of the Force Touch feature we see in the Apple Watch.

With 3D Touch feature, the phone's display will now have the capability to intuitively sense difference in finger's pressure to enable new gestures — Peek and Pop. Users can dip in and out of content without losing their place. Users just need to press the screen lightly to get a Peek at a photo, email, web page or other content, and if pressed a little deeper, they can Pop into the content itself.

Another related feature is the Quick Actions, which uses 3D Touch technology to provide shortcuts to the things users do the most, so they can send a message or take a selfie with just a simple press from the Home screen. [Check out the 3D Touch demo video, below]

Apple iPhone 6S and iPhone 6S Plus' 3D Touch featureApple via YouTube

After understanding the 3D Touch feature, now we will discuss the ways to tweak feature setting to adjust 3D Touch's sensitivity to match user's preference.

Step 1: Go to 'Settings' and select 'General'

Step 2: Look for 'Accessibility' option and select it

Step 3: There you find 3D Touch slot and tap it

Step 4: On entering 3D Touch setting options, you will find 3D Touch feature – on/off options and below it, there you will be find sensitivity options. Users will have three options to select – light, medium and firm. Thus you can set the sensitivity according to your preference.

[Note: Medium will be the default option]

[Credits: Redmond Pie]