I have tried reading the notes on the wing tip, but didn't understand well. How will the vortex be reduced on the wing tip.
Wing vortices cannot be reduced. It is a byproduct of creating lift. The various wingtip shapes help to combine the airflow from the top and bottom of the wing and can make the wing act like it is longer and creating the same lift, but the vortex is still generated. The biggest vortices are created by the big airplanes when they are heavy, dirty (lots of flaps, etc. deployed) and slow (i.e. takeoff and landing). Even my little 4-seat Cessna Cardinal creates vortices.
See Section 3.14 here http://www.av8n.com/how/htm/airfoils.html#sec-vortices of this great e-book "See How It Flies" http://www.av8n.com/how/
Vortices are shed along the entire span of the wing and are proportional to the lift produced. To reduce the strength of the vortex at any single point along the wing, including the wingtip, you can increase the span. This does not change the required lift or the total amount of energy going into the sheet.