If you are talking about executing another pipeline job, the "build job" step can accomplish this:
build job: '<Project name>', propagate: true, wait: true
propagate: Propagate errors
wait: Wait for completion
If you have paramters on the job, you can add them like this:
build job: '<Project name>', parameters: [[$class: 'StringParameterValue', name: 'param1', value: 'test_param']]