I notice you're looking for information about downloading xc.h. Let me clarify what this is and why you won't find a standalone download for it.
To download the XC.H library, follow these steps: xc.h library download
The only safe, supported method to obtain xc.h is by installing the official Microchip XC compiler suite. I notice you're looking for information about downloading
Download the installer (free or pro version – the free version is sufficient for standard use of xc.h). follow these steps:
The only safe
If you use VS Code, you must configure c_cpp_properties.json:
// Configure for PIC16F877A (example) #pragma config FOSC = HS, WDTE = OFF, PWRTE = OFF, BOREN = OFF, LVP = OFF, CPD = OFF, WRT = OFF, CP = OFF