When registering an Australian proprietary company limited by shares (Pty Ltd) you are presented with many options as to the legal element (ending/suffix). The full list is below.
These legal elements are legally identical. Therefore the choice as to which one to register is purely a matter of style and preference. That said, if you decide that you would like to alter the style of a legal element at a later stage then you will be required to go through the company name change process by submitting a Form 205 to ASIC with the $387 fee.