To correlate your Azure DevOps work item tickets with another ITSM app, you will need to create a Correlation ID field in the table whose data you are sharing out. This Correlation ID field will be populated with the corresponding ticket's sys_id or other form of unique identifier.
Procedure
To create user defined fields in the table whose data you want to share out of Azure DevOps, follow these steps:
Access settings
In Azure DevOps, click the Organization settings in the bottom-left corner.
Select Process
Under the Boards section, click Process. Then, select the process whose data you want to share out.
Select work item
Select Task as the work item type.
Create new field
Click New field. Then, set the Name field as Correlation_id and select Text (single line) in the Type field. Click Add Field when done.