Tax Year 2016: I didn't pay my taxes when filing. How do I pay them now?

[tmgrasso]

I filed my taxes, but opted out of paying at that exact moment.  I need to pay them by April, but don't know where/how to?

[KarenL2]

Here is the link to pay the IRS online.  There might be a fee for paying with a credit/debit card.   
https://www.irs.gov/payments  Also, I'll post the links to the states below.

Select the following options: Reason > Tax Return, Apply Payment to >  1040, Tax Period > 2016

How do I contact my state's Department of Revenue?
https://ttlc.intuit.com/replies/3302452