How to combine two windows as one in Terminal? In Terminal I can use Command + T to create Tabs in one Window, check below:

but now, I opened two windows like this, how to merge them as one liker upper:

I have tried drag one into another, but not work.
my macos Version is: Catalina 10.15.7 (19H524)
If you want to be able to drag one into another, you have to turn the Tab Bar on from the View menu, or use ⇧⌘T, and then drag the tabs.  Both the source and the destination need to have the Tab Bar turned on.
Or, from the Window menu... Merge All Windows.