Link your Instagram account with other social networking account such as Facebook, Twitter, Tumblr and Flickr so that your Instagram posts update may also appear on your other account. The following steps show you how to do that on iPhone in a few steps.
- Launch your Instagram from your iPhone.
- Tap button in the bottom-right corner to enter profile page.
Tap “Share Settings”
- On the Settings page, locate “Share Settings” and tap it.
- Choose the account that you want to link with your Instagram account and tap it. 
- Log in to the account that you are going to link with Instagram account.