You cannot change or add anything on the return that you just e-filed, nor can you stop it.  It is too late, just like when you put an envelope in a US mailbox on the corner.

If you left out a W-2, or a dependent, or a 1099 etc…DO NOT change your return while it is “pending.”  The changes will go nowhere.

Now you have to wait until the IRS either rejects or accepts your return.  If your return is rejected, you will be able to go into your account and make the necessary changes to your tax return and re-submit your return.

 If the IRS accepts your return, however, then you have to wait longer until it has been fully processed and you have received your refund.  THEN you can prepare an amended tax return. You have to be able to work from that return exactly the way it was when it was e-filed originally.  You will need to use a form called a 1040X. return.  

 Meanwhile, DO NOT go in and start changing anything on your return in the system, or you will make a mess for yourself.  Sit tight and wait until you see what the IRS does with the return you just e-filed

What does "Pending" mean?

Pending simply means that your e-filed return is on its way and that the government hasn't accepted or rejected it yet.

If you e-filed your return in January, it'll stay in Pending status until the IRS starts processing the backlog of returns.

After January, e-filed returns generally sit in Pending status for 24–48 hours before coming back as either Accepted or Rejected. Sometimes state returns stay in Pending for several days or even longer.

Keep calm and check back

Until your state or the IRS processes your return,  you may hear there's "no record found." That actually means the return's still being processed. Just check back in a few days.

Related Information:

• Why is my state e-file still pending?
• Can I cancel a pending return?
• What does Accepted mean?
• Why doesn't the government have any record of my pending return?
• Can I amend a pending return?