Does OEM unlock wipe data? I am using samsung galaxy j7, in the developer options there is a option "OEM Unlock" if I turn it on will it wipe my data? 

Also does samsung locks bootloaders? My device is not tied to any carrier.
Toggling the setting in Developer Options does nothing but allow the bootloader to be unlocked, however actually unlocking the bootloader will wipe all data, just toggling the setting in Developer Options will not. It would be more proper to call the setting "OEM Unlocking is Allowed". 

Otherwise here might be a good place to start looking for more information.