There are a number of ways that a transfer can be made. The most common method is bank telegraphic transfer where money is transferred electronically from a bank account in Singapore to your account overseas.
Alternatively one can also get the bank to issue a bank draft. This is similar to you writing a cheque to yourself from one bank account to another, except that a bank draft is recognised worldwide.
Bank draft is usually the cheaper of the two methods, but the time taken to complete the transfer is longer, and if the bank draft needs to be delivered from Singapore to where you are, then freight charges have to be factored in too.