Does anyone know/have the Fax number and or Address to send back requested information from a 12C letter? I lost the letter but have the information they requested. Thx!

See this link for more information.

The IRS is requesting Form 8962 for 2019

https://ttlc.intuit.com/community/health-care/help/the-irs-is-requesting-form-8962/00/27409

Yes I've seen that but it doesn't give any contact information for a mailing address. I am in need of a mailing address at this point so I can send this info in. 

The information that you need is on that Letter 12C, it is not necessarily the same for everyone.   If you are unable to locate it, you will need to contact the IRS and expect very long wait times.

Here is information on how you can reach the IRS by phone for further assistance:

https://ttlc.intuit.com/replies/3301592