Tax Year Prior to 2020: Tax Extension

[RAK46]

Used TurboTax Home/Business for 2017 and again in 2018. In January opted to file taxes by Feb 1st rather than paying est. taxes. However, will not have all the support forms necessary, specifically SSA1099, until after Feb1st. Should I file taxes without backup or file an extension?  If I file extension, which form should I use?

[KarenL]

You should wait to file your tax returns until you have all required forms. That said, there is no need to file any extension unless you cannot file by the due date of April 15, 2019.  If you need to file an extension, you would use Form 4868.  Please see this FAQ about How to File an Extenstion. 

Regarding any estimated tax payments, the IRS is a "pay-as-you-earn" system.  What that means is that each quarter, estimated tax payments are due (if not enough is withheld from W-2s or 1099s during the year) or there may be underpayment penalties and interest.  Filing an extension, and/or filing by Feb. 1st, doesn't prevent that if there is an underpayment of taxes owed.