How can I stop automatic posting to Instagram on Iconosquare?

You can toggle auto-posting on and off for any eligible posts as you're creating them in the Scheduler, as shown in the screenshot below:

If you'd like to turn off auto-posting permanently and receive a notification to post each time you schedule a post, follow these steps:

• Log in to your Facebook profile
• Go to Settings
• Select Business Integrations (https://www.facebook.com/settings?tab=business_tools)
• Find the Iconosquare app and click "View and Edit"
• Deselect "create post in your Instagram account"
• ​Click Save