Not sure how you think asking such a vague question is going to help you. TurboTax does not receive any information from the IRS after you file your tax return, so no one at TurboTax will know about a mailing you received from the IRS. You should read it all very carefully for yourself to see what it is about. When you have done that, then you could ask us some specific questions that we may be able to help with.
(what the letters from the IRS mean)
I GOT A LETTER FROM THE IRS
https://ttlc.intuit.com/questions/3605673-i-got-a-letter-or-notice-from-the-irs
I AM BEING AUDITED
If you purchased Audit Defense:
https://ttlc.intuit.com/questions/2924451-i-bought-max-or-audit-defense-and-now-i-m-being-audited
AUDIT SUPPORT
https://support.turbotax.intuit.com/irs-notice/audit-support/