Get the complete list of phonebook contacts inside the app.

We need to add two frameworks before proceed. Goo to Build Phase and Add these two:-

#import < AddressBook/AddressBook.h>
#import < AddressBookUI/AddressBookUI.h>

First step to get access permission to Contacts List or Phone book.

-(void)getList{

    ABAddressBookRef addressBook = ABAddressBookCreateWithOptions(NULL, NULL);

    __block BOOL accessGranted = NO;

    if (ABAddressBookRequestAccessWithCompletion != NULL) { // We are on iOS 6
        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

        ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
            accessGranted = granted;
            dispatch_semaphore_signal(semaphore);
        });

        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
        //dispatch_release(semaphore);
    }

    else { // We are on iOS 5 or Older
        accessGranted = YES;
        [self getContactsWithAddressBook:addressBook];
    }

    if (accessGranted) {
        [self getContactsWithAddressBook:addressBook];
    }
}

After getting access to phonebook we just need to create address book objects and set loop to retrieve name, phone number and emails down here:-

// Get the contacts.
- (void)getContactsWithAddressBook:(ABAddressBookRef )addressBook {

    contactList = [[NSMutableArray alloc] init];
    CFArrayRef allPeople = ABAddressBookCopyArrayOfAllPeople(addressBook);
    CFIndex nPeople = ABAddressBookGetPersonCount(addressBook);

    for (int i=0;i < nPeople;i++) {
        NSMutableDictionary *dOfPerson=[NSMutableDictionary dictionary];

        ABRecordRef ref = CFArrayGetValueAtIndex(allPeople,i);

        //For username and surname
        ABMultiValueRef phones =(__bridge ABMultiValueRef)((__bridge NSString*)ABRecordCopyValue(ref, kABPersonPhoneProperty));

        CFStringRef firstName, lastName;
        firstName = ABRecordCopyValue(ref, kABPersonFirstNameProperty);
        lastName  = ABRecordCopyValue(ref, kABPersonLastNameProperty);
        [dOfPerson setObject:[NSString stringWithFormat:@"%@ %@", firstName, lastName] forKey:@"name"];

        //For Email ids
        ABMutableMultiValueRef eMail  = ABRecordCopyValue(ref, kABPersonEmailProperty);
        if(ABMultiValueGetCount(eMail) > 0) {
            [dOfPerson setObject:(__bridge NSString *)ABMultiValueCopyValueAtIndex(eMail, 0) forKey:@"email"];

        }

        //For Phone number
        NSString* mobileLabel;

        for(CFIndex i = 0; i < ABMultiValueGetCount(phones); i++) {
            mobileLabel = (__bridge NSString*)ABMultiValueCopyLabelAtIndex(phones, i);
            if([mobileLabel isEqualToString:(NSString *)kABPersonPhoneMobileLabel])
            {
                [dOfPerson setObject:(__bridge NSString*)ABMultiValueCopyValueAtIndex(phones, i) forKey:@"Phone"];
            }
            else if ([mobileLabel isEqualToString:(NSString*)kABPersonPhoneIPhoneLabel])
            {
                [dOfPerson setObject:(__bridge NSString*)ABMultiValueCopyValueAtIndex(phones, i) forKey:@"Phone"];
                break ;
            }

        }
        [contactList addObject:dOfPerson];

    }
    NSLog(@"Contacts = %@",contactList);
}

Here I am printing (NSLog) the contact list array.
Happy Coding :)