Instagram no longer requires a connected Facebook Page to publish posts or view analytics in apps like Postpone. However, if you want to add music to your Reels, you'll need to link your Instagram account to a Facebook Page and connect it to Postpone via Facebook.
Prerequisites
Before linking a Facebook Page to your Instagram account, you must first convert your Instagram account to a Creator or Business account.
Creating a New Facebook Page
If you don't have a Facebook Page yet, you can create one directly from Instagram. Follow the steps in the official Instagram guide:
How to create a Facebook Page from Instagram
Connecting an Existing Facebook Page
If you already have a Facebook Page, you can link it to your Instagram account. Follow the steps in the official Facebook guide: