If you want to share o post outside Instagram, you need to get it’s link.
As with some other posts Facebook products, Instagram doesn’t play nice with others.
In our case, it’s not easy to share a post on other social platforms or chat app, other than Facebook’s.
You have just one option: to copy the link and manually paste it where you want.
Step 1: Tap the three dots button from the upper right cornet of the post you want to share.
Step 2: Tap the Link button from the shown menu.
That’s it, the link is now copied. You just have to paste it anywhere you like.