Having an Instagram Business or Creator come with many advantages including ability to use hashtag or view other business profile.
To use Instagram Business or Creator account with apps like OptiSigns, you will need link your Instagram account to a Facebook Business Page.
When you created your Instagram Business/Creator account. It should have asked you to connect to existing Facebook Business Page or create one. You probably reading this guide because you have skipped that step.
Here's how to link your Instagram account to Facebook Business Page:
Use your phone, make sure you have both Instagram and Facebook apps installed, and log in to the correct accounts.
Go to your Instagram app on your phone. Open Setting
Then tap "Business":
Then tap "Connect to a Facebook Page":
Then select Creating a new one or connecting to your existing one.
After this, it will open Facebook app asking for your permission to link the 2 apps and will take care of the rest for you.
Still need help? You can refer to official Instagram & Facebook guide here.