Why Android places the Back button on the left? [closed]

The reason is quite simply (contrary to your experience) that it's proven easier to reach the bottom left corner if you hold the device with your right hand rather than the bottom right corner.

1. Why is the back button on the left side?
2. How do I move the Back button on my Samsung phone?

Why is the back button on the left side?

It is placed in left side because for the right handed user it is easier for Thumb Tip to reach to the left side rather than retracting and bending down to the right side. Hope you got your answer, otherwise Try it out!

How do I move the Back button on my Samsung phone?

Step 1: From Settings, tap Display. Step 2: Scroll down and select Navigation Bar. Step 3: Choose your preferred Navigation Type. You can either allow the Navigation buttons to be permanently displayed on the screen or hide them by selecting Full-Screen Gestures.