Installing door to the basement

[Mibin Joseph]

Hi, our SFH in Loveland, CO has a finished 1100 sq.ft basement which is listed as STR. However, the entrance to the space is shared and not private. Could someone advise me on who are the people that I should be talking to see if this is a viable option? I also heard that some counties are not allowing homeowners to install basement doors? Also, is this private entrance going to add value to the home? Thanks!