are you sure you're referring to the correct form number? Public Law 115-97, repealed the disqualified corporate interest expense rules for tax years beginning after 2017. Form 8926 and its instructions will be obsolete for tax years beginning after 2017.
If I got a letter from IRS saying I need to send them a 8926 and a 1095-A for them to correctly process's my taxes what should I do?
First, does the letter say to amend your return or just send them the 8962? The letters I have seen in the past did NOT want you to amend your return.
Second, to create the 8962, you will pretend to amend your return, that is, you will follow the instructions to re-open your return (please see this TurboTax FAQ.) and add the 1095-A. However, unless the letter tells you to send the amended return to the IRS, just send the 8962 to the office that send you the letter.
If changes are required to your 1040 because of the 8962, the IRS office that sent you the letter will probably make the changes for you (which is why you may not need to send them the actual amended return).
Be sure to save the data in your return (don't try to e-file, but instead mark print and mail), so that your updates will be saved for next year's tax return.
In any case, do whatever the letter tells you.