Phabricator is an open source code review tool that can be integrated with Jira. There are a few steps that need to be followed in order to do this:
1) Create a new Phabricator (or update an existing one) repo that will hold the code that needs to be reviewed. Make sure to push all the relevant code to this repo.
2) In Jira, create a new project and link it to the newly created Phabricator repo.
3) Install the Phabricator Jira Connector plugin. This will allow communication between the two tools.
4) Configure the plugin with the details of your Phabricator and Jira instances.
5) Once the plugin is configured, code reviews can be created in Phabricator and linked to the corresponding Jira issues.