Does this hadeeth exists and what is it's soundness,"Whoever sends blessings upon me two hundred times on Friday,his sins of 200 years will be forgiven." Jazakallah

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

We do not know of any Hadeeth, whether sound or not, with this wording that you mentioned. However, there is a Dha‘eef (weak) Hadeeth whose wording is close to what you have mentioned. It is reported that the Prophet, sallallaahu ‘alayhi wa sallam, said: “Whoever invokes blessings upon me on Friday two hundred times, Allaah will forgive him for eighty years of sins.”

Ibn Al-Jawzi commented on that Hadeeth saying, “This is not an authentic Hadeeth.” [Al-‘Ilal Al-Mutanaahiyah]