To import contacts to Gmail:
- Create a custom CSV file, or export the address book from your other webmail provider or email client as a CSV file.
- Sign in to Gmail.
- Click Gmail at the top-left corner of your Gmail page, then choose Contacts.
- Click the More button above the contacts list and select Import....
- Click the Choose File button.
- Select the file you'd like to upload and click the Import button.
When it's done, Gmail will display the number of contacts imported.
Note: If you receive any error messages during the import, you might need to edit your CSV file.
About the notes field:
- Google Contacts doesn't support rich text formatting, or unlimited length in the “notes” field. When we're unable to import a certain field from the CSV, we do our best to let you know so that you can fix it manually.
- The maximum size for a contact is 128 KB. If a contact exceeds this size, the "notes" field might be truncated.
Are you interested in exporitng contacts as a Google CSV file and sharing them with a collegue, then please read: Exporting Gmail contacts as a Google CSV file to share with a colleague
Reference - Google Help - Contacts: Importing Gmail contacts