One of those agreements is that you license Instagram. With this you give Instagram permission to do everything with your content, to publish it, make it public and give others the right to do the same, for example. Well, Instagram does not Costa Rica Phone Number List specifically license otherrs to use your content, but there are of course a lot of features built-in with which content can be shared.
To Accepted need an external app
The fact that these functions are there is an implicit license to be able to use the content in that way. For instance: Share posts in a DM or in your Stories Share stories in which you yourself are tagged in Stories Embedding posts, for example on your website Share links to posts Share answers to question stickers anonymously in a Story.
That means that if it technical not possible within Instagram. Then it is not allo from Instagram either. It’s that simple! So you can’t just share someone else’s post on your own timeline. That is not possible with a function of Instagram itself. You need an external app for that or you need to take a screenshot. The same applies to taking a screenshot of a Story that you want to share as a post or Story.