Get your taxes done using TurboTax

You should file Maried Filing Joint as it is the most favorable filing status in which case both of you can claim the child.

If you file Married Filing Separate, only one of you can claim the child

To adjust your W-4to your satisfaction, see

https://ttlc.intuit.com/questions/1901003-how-do-i-change-my-future-paycheck-withholdings