How do you desinate yourself as a real estate professional in turbo tax?

It does not affect a business loss but allows you to be able to deduct your passive losses from rental property if your income would normally not allow it. The question is found in the Rental interview. (See the attached screenshot below. Click to enlarge.)

Qualifications.   You qualified as a real estate professional for the year if you met both of the following requirements.

• More than half of the personal services you performed in all trades or businesses during the tax year were performed in real property trades or businesses in which you materially participated.
• You performed more than 750 hours of services during the tax year in real property trades or businesses in which you materially participated.

Don’t count personal services you performed as an employee in real property trades or businesses unless you were a 5% owner of your employer. You were a 5% owner if you owned (or are considered to have owned) more than 5% of your employer's outstanding stock, outstanding voting stock, or capital or profits interest.

  If you file a joint return, don’t count your spouse's personal services to determine whether you met the preceding requirements. However, you can count your spouse's participation in an activity in determining if you materially participated.

Real property trades or businesses.   A real property trade or business is a trade or business that does any of the following with real property.

• Develops or redevelops it.
• Constructs or reconstructs it.
• Acquires it.
• Converts it.
• Rents or leases it.
• Operates or manages it.
• Brokers it.