In the Kanban board/ Scrum is there a way in JIRA to show the number of days each card is spending/ aging against each status ( Ex: Indev, code review, UAT, etc)
Note: new to JIRA, had used Rally where it used to populate automatically.
Welcome to the community.
Yes, there is a way to do this.
With your board displayed, click the ... button in the upper right corner and select Board Settings. On the next screen select Card Layout. Scroll to the bottom of that screen and you'll see an option to show "Days In Column". This will not show the number of days explicitly, but if you hover over the visual indicator (dots) that show in a card then hover text will show you how many actual days those dots represent.
This works for a Board associated with a Classic project. I don't know if there is a similar option for a Board associated with a NextGen project.