This process requires an existing GitLab git repository. For starters, the GitLab repository URL can be acquired on the repository project page. Choose between SSH or HTTPS.
Use this information to connect the GitLab git repository to your Jira server via Git Integration for Jira add-on.
The Git Integration for Jira add-on supports v3 and v4 of the GitLab API (in both Jira Cloud and Jira Server).