How do players trade items in Sword Spirit?

Two players stand closer, then press esc, and his name box will be displayed. Click, there will be trading options, but be sure to stand closer. There is also the use of Shenlong Industrial and Commercial Mail to find the person who mailed Shenlong Industrial and Commercial Mail, and then enter the name of the person to be mailed in the mail bar in the lower left corner, and then put things in, only three at a time, and this requires a mailing fee, and then send it out.