C:\Program Files (x86)\Labcenter Electronics\Proteus 7 Professional\LIBRARY
To add these library files to Proteus:
Once you have downloaded the .ZIP or .RAR file, follow these steps to integrate them: How to Import HT12E and HT12D IC into Proteus 8
(Note: This link redirects to The Engineering Projects archive, a trusted repository for Proteus component libraries.)
Search for "Proteus Library for HT12E and HT12D" on GitHub or engineering blogs like The Engineering Projects.