There is not yet an option available to post directly from Instagram’s official website, but the Creator Studio provides the opportunity to schedule both Instagram posts and IGTV videos.
The browser will show your Instagram and Facebook account if they are connected already. If not, then you have to connect them.
After connecting, tap on the Instagram option to check your Instagram content and stats. There will be a huge blue Create post icon present if you have the option to post through Creator Studio. You can opt for this option to upload the posts.