Which is the starting date of my contract

I have signed a contract on 17 March, 2018, and it is mentioned in the terms, the contract started on 06.12.2017, in this case, which is considered the starting date for my employment!! 17. 03 0r 06.12.

Hi,
It seems your contract was not ready when you actually joined in December 2017. So your contract is printed in March 2018 and your date of employment is Dec 2017.

When you sign your contract use the date of joining 06.12.2017