Xray REST API is your go-to for handling those heavy-duty or time-consuming operations. It’s got specific endpoints designed just for that.
Your first step is to get your hands on the token. This is based on the Client Id and Client Secret of your assigned API Key.
Once you’ve got that, you’re all set to make your requests to the Xray Cloud. Happy coding! 
The REST API base URL for all endpoints is https://xray.cloud.getxray.app/ .
Top right corner select 
to access Jira Administration & navigate to Apps.
From the left side menu look for "API Keys" under Xray Settings, and click it.
From the right-hand side of the page click the button "Create API Key".
Type in and select the User you want and proceed to generate a Client_id and Client_secret
(Video Description: How to get API Keys in Xray Cloud)