It is automatically set to medium after you install the mobile app.
You can change the priority settings by doing the following:

  1. Tap on “menu” which is located towards the bottom of the app.
  2. Tap on “Priority Settings”.
  3. You can select “Low,” “Medium,” or “High”.
※ You are charged the smallest handling fee if you set your app Priority to “Low.”
Please note that if you do this, it will take a long time for the payment to be reflected in your account.