Filing before you have all of your information causes you a lot of aggravation that could be avoided if you just wait until you have everything first and then take your time preparing your return so you do not mess it up because of a rush to get a refund.
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 and mail it in. 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. You cannot e-file an amended return. They have to be mailed, and it takes at least 2-4 months for the IRS to process an amended 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
filing without checking your return to make sure all income, deductions, and credits are entered creates a mess. you'll have to wait for the IRS to process your return or reject it. if rejected, you can make corrections without issues. on the other hand, if it's accepted, you may need to file an amended return pay the balance due and possibly await a penalty notice from the IRS. don't be in a rush to file. The IRS will not actually process the return until later in January so it just sits and you can not call it back to correct. if you are claiming certain credits, the IRS takes even longer to process.