What line should I enter 1099R_LS withholding tax from survivor annuity paid.

It sounds like you received a Form 1099-LS?

You would receive a Form 1099-LS if you are the acquirer of a life insurance contract, or any interest in a life insurance contract, in a reportable policy sale. See the Instructions for Form 1099-LS below, for complete filing requirements.

There is not a specific place to post a 1099-LS.  However, to take advantage of the premium payments, you would enter it as investment income as follows:

1. Go to the Income Section
2. Choose I'll choose what I work on
3. Scroll down to Investment income
4. Select Stocks, Bonds etc.
5. Answer No, you did not get a 1099-B
6. Type of investment you sold Everything Else
7. Description is 1099-LS Life Insurance, Amount, and Date
8. It may ask for the date a second time
9. Answer that you purchased the property
10. Then enter cost basis and date

Click here for 1099 -LS Instructions.

Click here for Revenue Ruling 2009-13, which discusses income recognized upon the surrender or sale of the life insurance contracts.

Click here for Revenue Ruling 2020-05, which discusses income recognized upon the sale of the life insurance contracts