Go to Jira Settings > Issues > Issue Type Scheme and select the Issue Type Scheme you want to add Xray Issue Types.
Drag-and-drop Xray Issue Types: Test, Test Plan, Test Set, Test Execution to Issue Types for Current Scheme.
Tip
If your project uses the Default Issue Type Scheme you only need to perform this action if you don't want to use all issue types.
At the Project Settings > Xray Settings > Summary you can check if Xray Issue Types are already available at your scheme.
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Your team does not have to use all Issue Types in their project. If you want to go for a simple approach you might only use - Test, Test Plan & Test Execution.
