Late-arriving CSF1099R

[tnsbss]

I eFiled my taxes on the 1st of Feb and the very next day, I received a CSF1099R from the Office of Personnel Management for ~$300 I received as a "death benefit" from my father's employment with civil service.   I had no idea this was coming.  I recall prevously receiving a lump sum pymt in this amount from OPM as a "lump sum death benefit"...not sure even why, it's such a small, odd amount.  My question is, since I eFiled already, can I eFile an amendment or does that need to be mailed in?  It seems silly for such a small amount the but right thing to do is add that ~300 dollar into the mix.   

[DoninGA]

If the 2023 federal tax return was e-filed then you can e-file the 2023 Form 1040-X amended tax return.

The Form 1040-X for amending a 2023 tax return will be available in TurboTax on 02/14/2024.

If the return is rejected you can make the necessary changes and e-file again.
If the return is accepted you will have to amend your original tax return. An amended return, Form 1040-X, can only be printed and mailed to the IRS if the original tax return was not e-filed. The IRS will take up to 16 weeks or longer to process an amended tax return.

Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.

See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...

[Opus 17]

Is it in your name or your father's name?  I'm also wondering why a "death benefit" would be taxable.  A pension payout would be, life insurance would not.  Is this something in between?  I suppose if they sent a 1099-R in your name, they think it's taxable to you, and you would follow DoninGA's advice on amending.  But it seems a bit odd.