I have no mortgage but turbotax asks "Who is your mortage lender? This occurs when I review my federal tax. How do I proceed?

You may be getting this message because you entered your property taxes on the entry screen for mortgage interest (which is OK if you have a mortgage). 

First, delete your property tax entry in the mortgage interview, by following these steps:

1. Click Federal > Deductions & Credits 
2. In the Your Home section, click the Start/Revisit box next to Mortgage Interest, Refinancing, and Insurance (Form 1098)
3. On the screen, Review your 1098 info, click the Delete icon (trash can) next to your entry.

Since you do not have a mortgage, enter your real estate taxes using these steps:

1. In the Your Home section, click the Start/Update box next to Property (Real Estate) Taxes
2. On the next screen, enter the property taxes you paid in 2018.
3. Click Continue when done.