Community-maintained libraries like maanjum95/Keypad_4x4 or 8051-Keypad provide free source files and examples.
Select the component and place it on the schematic workspace. Proteus 4x4 Keypad Library Download
Forgetting to add pull-up resistors. Many custom keypad libraries include internal weak pull-ups in the model; but if you see floating inputs, add external 10kΩ resistors from each column to VCC. but if you see floating inputs
If you download a custom .LIB or .IDX file for a keypad model, follow these steps to add it to your software: : Unzip the library files. Proteus 4x4 Keypad Library Download
The default installation paths are:
In Proteus, navigate to System > System Settings > Library Folder to manually add the directory where you saved your new library files.