Keep all answers short, simple and to the point as well as polite.  Respond to the notice with copies of all supporting documents attached as needed. 

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/