How do I link my Instagram to my Facebook page?

To link your Instagram account to Facebook page on Android:

Go to your profile and tap on the three vertical dots or the Settings button on top right corner
Scroll down and tap on the Linked Accounts then tap on Facebook
Login to your Facebook account
Your Instagram account will be linked to your Facebook timeline automatically.
To link a particular Facebook Page, tap on Facebook again, then select a page that you manage under the option Share To

To link your Instagram account to Facebook page on Android:

Go to your profile and tap on the three horizontal dots or the Settings button on the top right
Scroll down and tap on the Linked Accounts then tap on Facebook
Login to your Facebook account
Your Instagram account will be linked to your Facebook timeline automatically.
To link a particular Facebook Page, tap on Facebook again, then tap Share To, and then choose the Page that you manage and link it to Instagram