How to set the date and time on your Mac

1. Choose Apple menu > System Preferences, then click Date & Time.
2. Click Date & Time, then select to set the date and time automatically or manually.
   • Automatically: Select “Set date and time automatically,” then choose the network time server for your region.
   • Manually: Deselect “Set date and time automatically,” then manually enter the date and time. When you’re done, click Save.
3. Click Time Zone, then select to set the time zone automatically or manually.
   • Automatically: Select “Set time zone automatically using current location.”
   • Manually: Deselect “Set time zone automatically using current location,” click a location on the map, click the Closest City pop-up menu, then choose the city closest to your location.
4. Click Clock.
   • Show date and time in menu bar: Select the checkbox to see the date and time in the top-left corner of the menu bar. In “Time options” and “Date options,” set how you want the date and time to appear.
   • Announce the time: Select the checkbox to hear the time announced, then choose when you want it announced. If you want, you can customize the voice.

Cr : https://support.apple.com/kb/PH18804?locale=en_US