Time zones appear in 2 places in Recruiting as described here. 

Time zone at the company level

1. Go to People > Hiring > Applicant Tracking
2. Select Admin > Company Settings
3. Select Address, Time Zone
4. In the Default Time Zone section, use the drop-down to select a time zone. 
5. Select Save.
   1. Note: By default, when you create users, they have the time zone associated with your Company's account.

Account Info

1. Go to People > Hiring > Applicant Tracking. 
2. Select the Gear (settings) icon, then Account Info.
3. In User Information, use the drop-down to select a time zone.
4. Select Save.
   1. Calendar invitations use the Time Zone in this section. 

Understand how calendar invites change time zones 

Recruiting sends meeting invitations as .iCal files. Most calendar apps use this file type, like Gmail, Outlook, Yahoo Mail, and Apple Mail. 

When a recipient gets an .iCal invite, their calendar changes the meeting time to match their default Time Zone. 

How this works:

• The sender sets the meeting time in their own time zone.
• The recipient's calendar changes the time to their default time zone.
• This helps everyone join the meeting at the correct local time.

Example:

• Sender sets a meeting for 12:00 PM in Pacific Time (PT).
• The recipient uses Mountain Time (MT).
• The recipient will receive a meeting invite for 1:00 PM MT.