If you were legally married on 12/31/2018 then you can only file your 2018 tax return as either Married Filing Jointly or Married Filing Separately. Payment of child support does not determine if you file as MFJ or MFS.
However, if you did not live with your spouse at any time for the last six months of 2018 and you are claiming a child as a dependent then you may be able to file as Head of Household if you meet the other requirements. See this TurboTax support FAQ for Head of Household if married - https://ttlc.intuit.com/questions/2567672-can-a-married-person-claim-head-of-household-filing-status
Child support payments are not entered on your tax return as income.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.