Hi TungSon,
If I understand your question correctly, you are wondering why the Test and Evaluation Document is an output of Manage Quality instead of an output of Plan Quality Management.
Let's say we are building a house
In the Plan Quality Management process, we use Test and Planning to see what QA/QC method will let us test the house's quality standard. Let's say we are planning to use a checklist to confirm if every elements are present.
In the Manage Quality, we determine what items should go on the checklist. (ex. check electrical/plumbing, check air tightness, etc)
In Control Quality, it is when the actual inspection takes place. The filled-out checklist is output as Test and Evaluation Document Updates.
To answer your question, although during the planning phase we know that we are going to use a checklist, the actual checklist won't be produced until the Manage Quality process.
Hope this helps,
Joe