Hi Naresh,
Usually, you can start with "Dear Sir," then express what you want to convey to him using polite words. After finishing the email, sign off with your signature (save it and use the same sign in all your emails). For example:
Thanks & Regards,
Naresh
HR - Executive
Company Name
Tele/Extn
Email Id
If you are sending an email for his approval, mention the details first. After that, write, "This is for your kind information and approval for further movement or for further advice."
I hope this is clear for you to understand.
Regards,
Brinda