If ihave chosen to send a check instead of using my bank account to pay for my tax due, can i change it? and pay it online?

[silviavelarde]

federal tax due*

[TomK]

If you have already filed your return, and it has been accepted, then you can't change it.  If your return gets rejected, then log back in and change it.

Yes, you can make a payment directly to the IRS:  https://www.irs.gov/payments