Your contacts can include:
Personal contacts: These include contacts you import to Google Apps (say, from Microsoft Outlook or Lotus Notes), addresses of people you’ve emailed, and contacts you add directly to your Contact Manager.
Personal mailing lists: These are groups you can create in your Contact Manager to help organize your personal contacts, or to use as personal mailing lists. Learn more about personal contact groups
Global contacts: If your Google Apps administrator has enabled Shared Contacts for your domain, you can also access email addresses of everyone in your organization, as well as any outside contacts your administrator has added (such as vendors or suppliers)—much as you did with the Global Address List or Name and Address Book you may have used in Outlook or Notes.
Global mailing lists: Your administrator might create Google Groups that people in your organization can use as mailing lists. If Google Groups for Business is enabled for your domain, you might also be able to create global mailing lists yourself. Learn more about Google Groups
You can easily find email addresses when composing a mail message by beginning to type the address in a compose window’s To field. Gmail knows the addresses of all your contacts and mailing lists. It also remembers addresses of any other people you've corresponded with. When you start typing an address in an email message (or meeting invitation), a list of matching addresses appears. To enter an address, just click it!
Note: To see a global mailing list address in the autocomplete list, you might have to send mail to the list once.
To see a list of all your contacts when composing a mail message, open the Contacts Picker. Here, you can browse all your personal or global contacts, and you can search for contacts using the autocomplete feature (start typing to see a matching list of addresses).
To open the Contacts Picker, click the To: link in a compose window:
To view and manage your contacts, open your Contact Manager. From your Gmail window, click the Mail logo and choose Contacts from the drop-down.
Here, you can browse or search for contacts. You can enter profile information for contacts (business addresses, website URLs, and so on). And you can create personal contact groups, which can be used both to organize contacts and as personal mailing lists. (Global mailing lists are managed elsewhere, which we’ll get to below.)
When your Contact Manager first opens, it shows your personal contacts, which are listed in the My Contacts group. (If you haven’t yet imported or added any personal contacts, this list will be empty.) To see details about a contact, just click the contact.
My Contacts is just one of several default groups in your Contact Manager. Other groups you might see include:
My Contacts: Contacts that you've imported yourself, created in Contact Manager, or added from another group. Most mobile devices sync with this group, but some may sync with other default groups.
Most Contacted: The 20 addresses you use most frequently. Gmail automatically updates this list for you.
Other Contacts: Contacts that haven’t been added to My Contacts or any other contact group.
Directory: If your Google Apps administrator has enabled Shared Contacts for your domain, this group lists all the global contacts in your domain.
Starred in Android: You’ll see this group if you sync your contacts to an Android device. This contains contacts you've starred as favorites using Android.
Friends, Family, and Coworkers: These were default groups in previous versions of the Contact Manager. If you used them before, they can't be deleted.
Of course you can also create your own groups—both to organize your contacts, and to use as personal mailing lists. Learn more about personal contact groups
Open your Contact Manager.
Click the New Contact button.
Enter your contact's information in the fields. For additional fields, click More.
Click Save now.
Initially, the contact appears in My Contacts. But you can move it to another group, as described next.
Once you create groups in your Contact Manager, you can easily add contacts to those groups. You can add a contact to any number of groups:
Select the contact by checking its box.
Click the Groups button
Select the group you want to add it to and click Apply.
To quickly add a global contact to your personal contacts, select the contact in your Directory group, and click the Add to “My Contacts” button
Groups you create in your Contact Manager are just for your personal use. That is, you can send mail to your Cycling Team group, but other people in your organization can’t use that group address.
Global group addresses that can be used by everyone in your domain are instead managed by Google Groups. if your administrator has enabled Google Groups for Business, you can see these groups by going to your Groups service: At the top of your Gmail or other Google Apps window, click Groups. Then, on your "My groups" page, click Browse all groups. Learn more about Google Groups