In order to use Test Management in your JIRA project you need to enable it on the JIRA's project administration page.
1. Head to Project Administration by clicking on the gear-shaped icon, located on the upper right corner.
2. Select the desired project, and once the page loads, click on Adaptavist Test Management on the bottom of the left panel.
3. Now disable or enable Adaptavist Test Management.
4. Make sure you reload the page in order to apply the changes.