You can access these settings by going to Settings>Global>Account Settings
In Account Settings there are two tabs: Global and Business Info (see below).
In the Global tab, you can set the time zone your account will use from the Time zone dropdown. You can also enable the multi tab login if you want.
In the Business Info tab, you can set you Business Name, Customer Care Phone and Customer Care Email details for your account.
IMPORTANT NOTE: These settings will be applied for all channels.