You can put objects on a master page, and apply object styles to those.
Can you give us more details?
Thanks for the answer Peter.
If I already Place 100-page word document, and modified some of it, could it make applied to the newly made object style with master page?
Or is it any other way?
The term "object style" has a very specific meaning in InDesign, and I'm not sure that's really what you mean.
Are you saying you just want different margins on the left and right pages? You would do that on the master page (but I would enable Layout Adjustment first).
What version of InDesign are you using? Layout Adjustment moved from the Layout menu starting in CS6 and is now under Layout > Liquid Layout... and then the panel flyout menu.
You can definitely add the sorts of things you are talking about to an object style for text frames, and apply that style to the frames on the master page, but I won't guarantee that the change will affect the document pages after you've placed the text since that overrides some attributes. It definitely will not help if you did not use master text frames to start.