It's rare for a lender to ask for an MeF Submission ID (SID), but if they insist on it, you have to call TurboTax support to get it. Your MeF Submission ID is not anywhere in your tax return or in the TurboTax software.
Form 8879 is not used when you file your tax return yourself with TurboTax. Form 8879 is used only to authorize a paid tax preparer to e-file your tax return for you. You don't have to authorize yourself to file your own tax return. If someone is asking you for Form 8879, either they think you paid someone to do your tax return, or they don't understand how tax returns are filed.
You could try explaining to the person who's asking for it that you filed by yourself, or ask to speak to a supervisor or other higher-level person who knows more about how tax returns are filed. If that doesn't work, and you'd rather just make them happy instead of trying to convince them, here's what you could do. Download Form 8879 from the IRS web site. Fill in the top part, and parts I and II. Print the filled-in form and sign Part II. Make a photo copy of the signed form and give the copy to whoever is asking for it.
