To add a tag to a scenario in Jira, you need to open the issue. From here you can see where the tag button can be found, it is circled in yellow in the image below.
After clicking the tag button you will be provided witha list of tags that have already been created in-case these will apply to multiple scenarios. Alternatively, you can beign typing and then click on the box to create a new one.
After doing so the tags will appear in the feature files, either within the repository for a git connected project or once they have been exported as a classic project. It's worth noting that when the scenario relates to a Jira issue then a tag will be automatically created reflecting this relationship.
Behave Pro Classic and Trunk-Based Development Tags
If you are using either a classic style project or are using Git integration with a trunk-based development approach; Behave Pro will create additional tags.
Since you are able to create features and scenarios directly from the Requirements page, it is possible to make these unrelated to a Jira issue; as a result these scenarios will be given an ORPHAN tag to show that they do not belong to an issue.
In addition to this there are status tags, the available status tags are, Open, WIP (Work-in-progress) and Completed. The tag allocated to your scenario depends on where the issue is located on your Jira board; the tag status it applies in that position depends on the configuration of your Jira board.