Turbo tax wants me to enter a K1 that is no longer active how do I show that we ended the partnership in 2018?

in your TT filing for 2018 you should have indicated it was final k-1 and enter sales info even if you got $0 (that would be the sales price) - don't know if you had any remaining basis. without entering sales info any suspended losses would not have been allowed so if that's the case you need to amend 2018

so on the 2019 return delete the k-1

https://ttlc.intuit.com/questions/2903043-how-do-i-delete-a-k-1