“Read-only password” is also referred as “Investor password”.
This password is provided to someone who does not trade or is not allowed to trade.
If you login to your account with “Read-only password”, you can see trading histories, account balances and etc but cannot trade or change other settings.
Normally, money managers use the password to let clients see their trading activities.
If you are not provided with “Investor Password” yet, you can change/reset the password directly from MT4 or MT5 trading platforms.
For any inquiries regarding to your login details of MT4 and MT5 accounts, please contact the support team of your broker.