you don't need to specify it's a second home but you can either use "second home" or address as the description. you enter it through the investment section
see this link for how to enter
https://ttlc.intuit.com/turbotax-support/en-us/help-article/real-property/enter-sale-second-home-inh...
in addition, if there's a loss on the sale you must indicate that the loss is not deductible - there is a question about the loss being nondeductible further on after entry of the sale (the code is L)
