Basic requirements for a Jenkins shared library to be used in a Pipeline Code are -
A Repository with pipeline shared library code in SCM.
An appropriate SCM Plugin configuration for the Jenkins instance.
Global Shared Library should be configured in Jenkins Global configuration.
Include the Shared Library in the Pipeline Code and use the methods defined in the Jenkins Shared Library.
E.g.
#!/urs/bin/env groovy
@Library('fs_jenkins_shared_library@v2.0.7')_
