Having push notifications enabled in House Flip allows the game to remind you when offers come in, renovations finish, or other updates. If you wish to manually enable/disable these notifications, please follow these steps:

First,
  1. Go to your in-game SETTINGS
  2. Tap NOTIFICATIONS
  3. Tap ALLOW
If that doesn't work,
  1. Go to your PHONE SETTINGS
  2. Tap NOTIFICATIONS
  3. Scroll down to House Flip, and tap on it
  4. Change your desired settings
Once you've made the changes, simply return to your home page.