Like JSU on Jira Server, Jira Cloud proposes a "Field required" validator in transitions.
However, when fields are set as required in the workflow, they do not appear differently from optional fields in the screen.
It is a big step backwards, and it can lead to confusing results.
- JSU on server proposes the best option: a red asterisk appears next to the field name.
- Jira Cloud could propose the same functionality
Some community members suggest setting up directly a red asterisk or a "required" information in the screen name, but this workaround is way too rigid is some business cases.
At no point is the required field visually highlighted.
Making the field required by specifying field behaviour in a field configuration (instead of via workflow validator) produces visual indicators.