Thank you for choosing Adobe Premiere Pro.
I understand that you wish to edit a video using Adobe Premiere Pro and then upload it to Instagram later. Adobe Premiere Pro provides an option to publish the video online(Youtube, Facebook etc) Share your created movie | https://helpx.adobe.com/in/premiere-pro/how-to/export-video-share-social-media.html
For specific to Instagram, here are few links from other Adobe users:
I hope it helps.