It is for your dependent.

E-file reject IND-996: The Dependent/Qualifying Person Identity Protection Personal Identification Number (IP PIN) provided on the return is not valid.

If a dependent or qualifying person listed on your return has ever received an IP PIN, a CP01A notice, or opted into the IRS's IP PIN pilot program, that person's special 6-digit IP PIN needs to be on the return to validate their identity for e-filing.

Start by finding your dependent or qualifying person's 6-digit IP PIN. Here's how:

• Look on the CP01A letter they received in December or January for their 2021 taxes. IP PINs from prior tax years won't work.
• If they lost or never got a CP01A letter, retrieve their IP PIN online at the IRS's Get an IP PIN site.
• If unable to retrieve their IP PIN online, you can have it reissued (allow up to 21 days). More info

• Look on the CP01A letter they received in December or January for their 2021 taxes. IP PINs from prior tax years won't work.
• If they lost or never got a CP01A letter, retrieve their IP PIN online at the IRS's Get an IP PIN site.
• If unable to retrieve their IP PIN online, you can have it reissued (allow up to 21 days). More info

Then, follow these instructions:

1. Sign in to TurboTax if you haven't already signed in.
   • Mobile users, you'll need to sign in using your browser, not from the TurboTax app.
2. Select any "Fix" buttons you see before proceeding to the next step.
3. At the Welcome back to TurboTax message, select Fix It Now.
4. Follow the on-screen instructions to enter your dependent or qualifying person's 2021 IP PIN and re-file your return.

https://ttlc.intuit.com/community/rejections/help/ind-996-the-dependent-qualifying-person-identity-protection-personal-identification-number-ip-pin/00/27181

I have 2 dependents, so who do I use the IP-Pin for because I tried both and it didn't work

Did you get the CP01A notice ?   It is sent to the person who has to use it ... so which child was the notice mailed out to ?   And are you using the one issued this January ?    You cannot use the last year's # on this year's filing.  

I have never use an IP-Pin. And I never received a notice. And my return keeps rejecting 

OK ... so if the IRS says they issued an IP PIN for the child then you must either use the IP PIN to claim the child  OR   remove the child from your return.   If you did not request an IP PIN for the child then someone else did ... could it have been the other parent or someone else eligible to claim the child ?  

https://www.irs.gov/identity-theft-fraud-scams/retrieve-your-ip-pin

Thank you @bluedeb!   Your info was very helpful!  I have a question if you have a minute?

On Saturday (this weekend), I got my 2023 tax return ready (with TurboTax Deluxe), 

and was surprised to get a rejection with IND-996.   

Definitely got confused with the 5 digit code each filer fills out, and tried that a few times (my Wife and I), few more rejections.    Then finally found this thread, Thanks!!!

We actually never had IP PINs, so created them thru the website, entered the pins in the Federal Other section, saved the file, and re-submitted again, and got rejected.

Our last ditch effort will be to get our son to create one who's in College, and claimed as a dependent.    

My Question:   Thinking ahead on this less than fun experience, after resubmitting with our Son's IP PIN, think there will be some other downward cascading odd ball issue that will come up?

Thanks!  Adam70