You will need to head to the "My Account" section, find the MetaTrader account you would like to remove and click/tap on view.
Next, you will be on the MetaTrader account view.
Click/Tap the "Actions" tab
Click/Tap the "Remove account" button.
A notification will pop up asking for you to confirm the removal of the account.
This is an irreversible action. You will also not be able to remove an account with a negative balance until the account/s have been brought back to a Zero balance.
Click/Tap "Yes" on the pop up (or click "no" to cancel)
A notification will pop up confirming the removal of the account, you just need to click/tap "Ok".