This platform offers verified symbols and footprints. You can search for the HT12E and HT12D directly and download them in Proteus format.
Since direct links change, use the following proven method: Ht12e And Ht12d Proteus Library File Download
C:\Program Files (x86)\Labcenter Electronics\Proteus 7 Professional\LIBRARY Copy Files : Paste the downloaded files directly into this Restart Proteus : Close and reopen the software to refresh the database. Search for Components Schematic Capture This platform offers verified symbols and footprints
(decoder) are direct replacements that function exactly like the HT12E and HT12D in simulations. Search for Components Schematic Capture (decoder) are direct
If the library files above do not work for your Proteus version (8.9 or 9.0), let me know in the comments – I’ll share updated files.
If you cannot find a working library, you can with the same encoding/decoding logic, or create a schematic component with a virtual terminal.