A large proportion of smartphone owners choose to save their contacts to the phone rather than their SIM card because SIM cards offer a limited space when it comes to the number of characters you can have in names, and the type of information that can be included, pictures for example. However, if the phone needs to be restored to factory default, you'll lose all your contact information. This is where copying your contact to a SIM card comes in./ At least then you'll have a record of all the names and numbers you need. Here's how to do it on an Android device.
Select Contacts from the Home Screen
Press the menu button and choose More. From the list displayed select Copy Contacts
Two choices will be displayed. You can either copy contacts from the phone to the SIM or the other way around. Press SIM to Phone. Next you'll be asked to select individual contacts or copy everything make sure the box next to Select All in check. Press Copy.
Your contacts will now be copied across. The phone will alert you once the process has been completed.