Hi Niwantha,
Some words naturally collocate in English, while others do not. "Off" means to depart from a certain place with a destination in mind.
Example: I am going off. / I am off to school. / I am off to Europe. (The preposition "to" is required to show the meaning of direction of motion.)
It sounds unnatural to write or say: I am off to home.
It would be more natural to say: "I am heading home" OR simply "I am going home."
Hope this helps.
Cheers,
Lance