If you have access to your current MetaTrader password and wish to change the password from your iOS device, you have to go through some simple steps first.

• From your MetaTrader, tap the Setting button. 
• Tap the Account you wish to change the password to.
   
• Tap the 3 horizontal dots. 

  
  

• Tap Change Password.
    
• Tap Change Master Password.
  
  

  

  
  

• Insert your Current Password, type in your New Password and Confirm the New Password in the given blank space.

  
  
• When done, tap Change. 
• Your password is now changed.