Since you cannot simply "open" an IPA file on your iPhone, you need a sideloading tool. Method 1: Sideloadly (Recommended)
tweak allows the OS to ignore signature checks, enabling a permanent installation of any Facebook IPA without seven-day re-signing limits. Filza File Manager facebook+ipa+for+ios+935+best
Newer versions of iTunes removed the App Store, but you can still download iTunes 12.6.5 , which includes app management. Download and install iTunes 12.6.5 on your computer. Log in with your Apple ID and "buy" Facebook (it’s free). Go back to your iOS 9.3.5 device’s App Store > Purchased tab to download the older version. 3. Jailbreak & Checkmate, Store! (Advanced) Since you cannot simply "open" an IPA file