MyBB Community Forums

I want to put a option named 'Move To Trash', in my Inline Thread Moderation.how can I do that???

Create a Custom Moderation Tool for it.
ACP > Configuration > Moderation Tools > Add New Thread Tool.
Give it a name and a description and choose to Move the thread to a special forum called "Trash" for instance.

You'll need to create that Trash forum manually first.