How to use advanced settings features on Samsung Galaxy smartphones

Advanced settings
You can customize additional accessibility features and services for your device.
TIP Additional accessibility apps may be downloaded from the Google Play store.
Accessibility shortcuts
◌ From Settings, tap Accessibility > Advanced settings and tap an option:

• Quick panel buttons: Choose buttons to add to the Quick settings panel.
• Accessibility button: Choose an accessibility shortcut for the Accessibility
  button.
• Side and Volume up buttons: Configure selected Accessibility features to
  open by quickly pressing Side and Volume up buttons at the same time.
• Volume up and down buttons: Configure selected services to turn on when
  you press and hold the Volume up and Volume down buttons for three
  seconds.

Notifications
◌ From Settings, tap Accessibility > Advanced settings and tap an option:

• Flash notification: Flash either the camera light or the screen when you
  receive notifications or when alarms sound.
• Time to take action: Choose how long to show messages that ask you to take
  action, but are visible only temporarily (like notifications)