To backup your Seed Phrase, just open your eCredits Wallet App, go to the Settings menu, "Security Settings" and then "Wallet Security".  

Once there, you should see this screen: 
  

Click "Seed Phrase backup", and authenticate yourself with your PIN or Biometrics (depending on your settings). Once authenticated, you’ll have the option to set a backup password (will be required when you import your Seed Phrase from a backup) or skip it.

 Once you’ve set your backup password (or clicked “Skip”) you’ll see this screen:  

To save your Seed Phrase click “Store”. The system will open your phone’s standard file sharing window and send you an encrypted file containing your Seed Phrase. Be sure to save it in a secure but accessible location so you can import the Seed Phrase when necessary. 

Once you have stored your encrypted file you will have the chance to create another backup, or click back from the top left side of the screen to exit security settings.

Important! 

To import your Seed Phrase, locate and open the encrypted file within the eCredits Wallet App, and enter your backup password if you set it.