After you file

Thank you both for the replies.  I can send a check payment along with the amended return in the same envelope to mail?  The instructions said to write in my social security number.  Do you think it is ok if I don't write the SSN on the check?

 

If I decide to do electronic payment/direct pay online, do I need to wait until IRS receives the amended return I mail and post to "where is my amended return" site, or to wait until they actually process the return, which could take up to 16 weeks?  Or can I pay online using the IRS site right after I mail the amended return?  I am concerned that there is nothing in their system to match my online payment if I make the payment online in advance (separate from the paper return) and there is not a return to match in the system for a number of weeks.  Thank you.