Importing and exporting contacts from webmail

If you want to import contacts to Roundcube, you can use a CSV file (such as can be produced by Excel).
Roundcube requires specific column headings in the CSV file, to match either MS Outlook, Thunderbird or Atmail.
These are:
MS Outlook 2010

Anniversary
Assistant's Name
Assistant's Phone
Birthday
Business City
Business Country/Region
Business Fax
Business Phone
Business Phone 2
Business Postal Code
Business State
Business Street
Car Phone
Categories
Company
Department
E-mail Address
E-mail 2 Address
E-mail 3 Address
First Name
Gender
Home City
Home Country/Region
Home Fax
Home Phone
Home Phone 2
Home Postal Code
Home State
Home Street
Job Title
Last Name
Manager's Name
Middle Name
Mobile Phone
Notes
Other City
Other Country/Region
Other Fax
Other Phone
Other Postal Code
Other State
Other Street
Pager
Primary Phone
Spouse
Suffix
Title
Web Page

Thunderbird

Birth Day
Birth Month
Birth Year
Display Name
Fax Number
Home Address
Home Country
Home ZipCode
Mobile Number
Nickname
Organization
Pager Number
Primary Email
Secondary Email
Web Page 1
Web Page 2
Work Phone
Work Address
Work Country
Work ZipCode

Atmail

Date of Birth
Email
Home Mobile
Home Zip
Info
User Photo
URL
Work City
Work Company
Work Dept
Work Fax
Work Mobile
Work State
Work Title
Work Zip

You do not have to include all the fields.
Note that spaces and letter case are significant.