Open the “System Settings” and go to the “Mouse and Touchpad” section (Note that if you have installed Cinnamon desktop in Ubuntu, make sure that you are accessing the System Settings for Cinnamon Desktop, not the System Settings for Unity/Ubuntu. They are two different applications with the same name).
Click on the “Touchpad” tab. Under the Scrolling section, select “Two-finger scrolling” for the Panel Layout dropdown. The default setting is “Edge scrolling”, which means you can scroll the page by sliding along the edge of the touchpad.
You might also want to check the box “Enable horizontal scrolling” to be able to scroll sideway with your touchpad. Close “System Settings” and enjoy two-finger scrolling on your touchpad. Image credit: Blogging?