How do I file for a property tax refund once my tax return is efiled.

The MN property/rent credit form cannot be e-filed.   You had instructions on the screen that told you to mail it.    The forms will be in the pdf of the return.  You can print it out and mail it.

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-get-a-copy-of-a-return-i-filed-this-year-in-turbotax-online/00/25932

https://ttlc.intuit.com/questions/1899893-can-i-file-my-m1pr-minnesota-property-tax-refund-through-turbotax

https://www.revenue.state.mn.us/homeowners-homestead-credit-refund

https://www.revenue.state.mn.us/renters-property-tax-refund

To check the status of the rent credit in MN

http://www.revenue.state.mn.us/individuals/individ_income/pages/draft-wmr-context-page.aspx

https://www.revenue.state.mn.us/wheres-my-refund

To obtain the refund, the taxpayer must have a CRP, Certificate of Rent Paid (CRP), for each rental unit lived in during the year. The taxpayer's landlord is required to deliver a completed CRP to the taxpayer no later than January 31st of each year.

You will need the CRP to determine your refund, if any, and you must include what is called a Form M1PR with the CRP when it is filed. These forms have to be printed and mailed in to:

Minnesota Property Tax Refund
St. Paul, MN 55145-0020

TurboTax will prepare the Form M1PR for you to print. Towards the end of the step-by-step interview for Minnesota you will reach the Other Forms You May Need screen. To have the M1PR prepared and made available for printing, make sure you check the Property Tax Refund (Form M1PR) check box on the Other Forms You May Need screen, then follow the prompts through the end of the interview.

You can also file your M1PR free of charge at the MN Dept. of Revenue Property Tax Refund site, and if you're a homeowner, you can e-file it through the MN DOR's Property Tax Refund Online Filing System.