Why Doesn’t My Instagram Account Show Up In The Conversations Inbox?

Below are details about a feature or functionality that is no longer offered in new subscriptions starting after January 13, 2021.
Only Instagram Business Accounts will appear in the Conversations inbox. If you are using a personal Instagram account, you will not be able to use Conversations with it. However, Instagram does allow you to convert a personal account to a business account and you can find the instructions on how to do that here: Set Up a Business Account on Instagram.