Answer by Hitesh Chavda:
How to know which side I need to place paper for printing.
If paper is blank then no matter which side you put paper in printer, but If you want to print particular side of paper. some printer may print above the paper and some may print below the paper. so the solution is, try to find the icon as shown below, near your printer paper tray.
If the icon is looks like left (lines on paper) It will print paper on top.
If the icon is looks like as right (lines below paper) It will print bottom of the paper.
So Next time you print just remember this.