I need to knkw how to add a 1099-R form to my 2020 taxes that i already submitted?

[Critter-3]

If you have already filed and the return is pending it is too late to make any changes  UNLESS the return gets rejected ... then you can make any changes needed and refile. 

Can I change my return if I already submitted it and you’re holding it until the IRS opens?

No. Once you submit your return, it’s considered to be in pending status. We’ll hold all returns submitted before the IRS opens and submit them when the IRS is open.  Processing of returns is expected to start on or about 2/12 however some returns may be pulled earlier in test batches so watch your email for alerts. 

Once the IRS either accepts or rejects your return:

• If your return is accepted: If you want to change your return, you’ll need to amend it AFTER the original return has fully processed an you have the original refund in hand or have paid the original balance due.
• If your return is rejected: We'll send you an email to notify you, along with instructions on what to do. You can then open your return and make any changes you would like. Just be sure to fix the reason the return was rejected as well.

[Mtscam]

How do I get a copy of 1099R  for taxes??

[MayaD]

You will receive a 1099R form if you received a distribution of $10 or more from:

• Profit-sharing or retirement plans.
• Any individual retirement arrangements (IRAs).
• Annuities, pensions, insurance contracts, survivor income benefit plans.
• Permanent and total disability payments under life insurance contracts.
• Charitable gift annuities, etc.

The deadline to send the 1099R is January 31st so you might receive in the few days.

Contact your financial institution to get your copy. Most financial institutions have them available on line in your account.