If you're using an iPhone, you can customize which alert styles are shown (lock screen and banners) and whether the banners display momentarily or stay on-screen until dismissed.
Set custom notification settings on the iPhone
- Open the Settings app
- Tap Notifications
- Tap SubAssistant
- On this screen:
a) ensure Allow Notifications is enabled
b) Set alert styles to your preference
c) Set Banner Style to Persistent
d) Enable Sounds and Badges