When you print your returns to mail it will ask you to pay the fees. You can say to mail a check for the tax due and efile your returns then pay when or how you want. Although the tax due is due by April 15.
How to mail a return from the Online version
https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online/00/26258
Be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.