Apple Mail is the default email application in Mac OS X's. In Mac Operating System, Apple Address Book is also available which appear as general contact manager but it's capable of so much more. Apple Address book is basically a central repository of information which can be accessed and used by multiple applications. So for any communication, internally or externally the most required thing is contacts.
MS Excel is very popular among users for managing contact information as it maintains the data in tabular format. So, if you have your contacts information's like email address, home address, contact number, website etc. managed in Excel sheet and now want to import all contacts from Excel spreadsheet into Apple Address book then follow the below mentioned steps.
Check here complete guide of exporting contacts from Excel sheet into vCard file format so that VCF file could be further imported into Apple mail.
The process of importing contacts from Excel sheet into Apple Address book is accomplished. Now you can easily access all your contacts into Apple mail which were previously stored in Excel sheet.