Custom Fields in Outlook are an advanced topic. If you don't consider yourself to be 'tech savvy' I would suggest you don't use custom fields.
Outlook contacts have more than 100 standard fields which you can use to sync information from MailChimp - for both MailChimp merge fields and MailChimp Groups and Interests. Where possible we recommend you use a standard field for any MailChimp data
Use Outlook Categories for all Group Fields
We recommend that you sync all your MailChimp Groups and Interests fields with the Outlook Categories field (you can map more than one MailChimp Group to Outlook categories - it works just fine).
Outlook also includes 4 user fields for you to store your 'special field data' in - you can find them as User1, User2, User3, User4.
If you really MUST define your own custom fields, or you already have and you want to use them in the sync, ChimpySync will let you.
Using Custom Fields
Go to the Map Fields form and select 'Use Custom Field'.
Type the name of custom field you want to use:
*If you have already added a custom field in Outlook, this must match exactly the name you have added. If you get this wrong, ChimpySync will not see any existing data in your custom Outlook field, and will add any new data to a field with teh name you just specified.
The field will show up in the list of Mappings - with a * in front of the name to indicate it is a custom field.
Custom Fields in Outlook
By default you will not be able to see your custom fields in Outlook. (This is one of the reasons we say this is an advanced topic)
If you are in a view of your contact folder which shows as a list ( To get this select VIEW > CHANGE VIEW > LIST )
Right click a column header and select 'FIELD CHOOSER'.
Select NEW and add a new field EXACTLY the same custom field name you specified - or are using in your contacts.
You should see your new field in the form.
Drag your new field from the form to the headings in your Outlook list. This will add a new column to your list based on your field. You can rearrange the order of the fields by dragging and dropping; or add / remove fields using the Field Chooser.
This shows you how to view custom data in Outlook.
Viewing custom field data in Outlook contact forms, and editing custom field values in Outlook is beyond the scope of this article. Please search the MSDN web site for more information.