The Reposting feature allows you to upload existing posts (from you or other profiles) by ensuring the original source is attributed.
Please respect author's copyrights. See Instagram's Help for more information regarding copyright.
To repost a post:
Right-click any post, then select
Repost Photo/Video/Carousel Post… from the contextual menu.
When viewing the Details of a post, select the
Repost Photo/Video/Carousel Post… item under the actions button in the title bar.
You cannot repost items if the author has their profile marked as private. The repost menu items will not appear if this is the case.