Write text with echo() after reloading page with header()

I have page called account_settings.php and it's consist of change password, change profile pic, change user details (name, bio etc.). My question is how to write message with echo() after redirecting page with header().

Something like this:

if (true) 
{
    Do_Some_MySQL();
    header("Location: account_settings.php");
    echo "Success!";
}
else
{
    echo "Error!";
}

Thank you for all replies. ;-)