@smilemukul: setting up pubkey authentication has been discussed many times on the forums (and a 'net search will also turn up a plethora of hits).
As AlucardZero says, on most (all?) Linux distros, scp is included as part of the OpenSSH package(s). Earlier you said:
Originally Posted by smilemukul
This user have only been granted securing coping of files through another system but without ssh.
So - what gives? We can't help unless you're able to clearly communicate your requirements and circumstances.