This page refers to Portfolio classic plans. If you are currently running Portfolio 2.0, please check this link to access the latest page version.
Portfolio for Jira classic plans allow you to manually import issues from Jira and commit changes made in Portfolio for Jira back to Jira.
If you add new issues in Jira, you'll have to manually re-import them into your classic plan. However, if you use live plans, you'll be able to select your issues sources and automatically stay in sync with Jira.