When you first navigate to your Ads Manager settings, you'll be presented with the ad account setup.
We automatically assign you a random account ID number, and set your currency and time zone based on where you're located.
You may want to change these settings in the future. For example, you may relocate your business or start doing transactions in a different currency. Or maybe you set up your Facebook business account while travelling and need to change your time zone.
The Settings menu is where you can change these options.
Select
Change Time Zone or
Change Currency.