I have a Change Request work item. From here I want to create a child work item of Task type in which all the attribute values will be same as the parent work item.

I know that there exists a "extract work item from selected text" function in the top right corner which can help me achieve this, but it takes me through 3 windows. (to select the relationship, to select the type, to select the fields i want to copy). But I want to be able to achieve this programmatically because I only require a child parent (or a custom) relationship with a Task work item type alone.

How can this be achieved?

Thanks to all the helpful users posting on these forums,
I know how to add a link programmatically.
I know how to create a new child task work item with copied attributes.

All I need to know is how do I trigger this action.

Can a new button be added near the "extract work item from selected text" or "find potential duplicates" functionality button (top right corner)?

Can a trigger be fired when creating a new custom or child link in the links tab?

If yes, which are the extension points I can use?