GPIO pins 19,21,23,24,26,35,38,40 are dedicated for SPI protocol. Is it possible to use other GPIO pins for SPI? If yes, how do we do it?
The Pi has hardware support for the Pi acting as a SPI master. It has no support for the Pi working as a SPI slave.
That being the case it is simple to bit bang the SPI master protocol in software (as the software controls the SPI clock as it is the master). Using bit bang allows you to use any spare GPIO for any of the SPI signals.
Just search for SPI master bit bang software and implement your preferred solution.