If you have already e-filed and there were no prompts to mail anything, you are done. Unless the software told you to mail something, there would be no need to mail anything unless the IRS or your state contacted you requesting more information. You can see more details below for when you may be required to mail something in when filing.
NOTE: If you owe taxes and did not setup an auto-debit for them to withdraw from your bank account, then yes, you will need to either mail them a check or contact them directly to pay what you owe.
If you have already e-filed and there were no prompts to mail anything, you are done. Unless the software told you to mail something, there would be no need to mail anything unless the IRS or your state contacted you requesting more information. You can see more details below for when you may be required to mail something in when filing.
NOTE: If you owe taxes and did not setup an auto-debit for them to withdraw from your bank account, then yes, you will need to either mail them a check or contact them directly to pay what you owe.