Refer the link: https://developers.facebook.com/blog/post/2021/01/26/introducing-instagram-content-publishing-api/
What is it going to change? [I’m a non-technical person] What is the meaning of ‘API published post’? How to publish post through API? What extra features do we get if we publish our Instagram Posts through API?
Nothing is going to change. Unless you are using an automation tool that doesn’t support post scheduling, they might be able to offer that feature after these changes.
There are no extra features, it will just allow you to schedule your posts ahead of time and the software you are using for automation can post directly to your Instagram account using the API.
well, from what I understood, IG will allow business accounts users to use the third parties apps for posting witch is great and they will allow the API calls.
API calls are what used from the app to IG to get specific information about users, like for example we need API calls to get the number of followers/following, API calls to get the number on hashtags …etc
This is obviously their own App that will have only posting purposes but probably with more advanced options for posting.
As far as I could understand this goes for cooperative 3rd. party apps who are “IG varified” and not any 3rd. party business app. If I have understood correct.
I have already seen ads on IG from a couple. One app even allowed you to see those potential profiles who are checking out your profile without following. I don’t remember the app name though.
nice catch Micky I did not think about that, yeah they most likely allowing only verified 3rd parties, of course, that IG 
looking for profit everywhere.