To make use of more than one Live MetaTrader account and be able to switch in between them, follow the steps below
You need to:
Click/Tap on "File".
Click/Tap on "Login to Trade Account".
Enter the login information of the new Live Account that you wish to log into.
Click/Tab on "Login".
Your newly added account will be visible in the "Accounts" sub-section in the "Navigator" section.