Most probably, this board is a nextgen type of board, not supported for the Requests feature.
​
You can always check the type of board in your Jira account:

https://support.atlassian.com/jira-software-cloud/docs/get-started-with-next-gen-projects/
​
Even though nextgen boards are not supported in requests, they are supported in the "Task responses" feature; check it out!