Please know that to import the pin code in bulk we have follow below steps.

Step 1:  To upload the pin code in bulk you have to login to your admin panel

Step 2:  Then go to Multicity -> Minor/Sub City -> import  then you will two buttons Click on Export it will download the csv file  Please see  the attached screenshot 

Step 3: Now add the new data to the file and save it 

Step 4: Now again go to Multicity -> Minor/Sub -> import  the same place where you have downloaded the csv file and click on import button and select all necessary check box and upload the file  please see the attached screenshot

Step 5:  Now refresh the minor city. it will be added. 

Note: If you have same pin code for many places it will upload only one data. so rest of data you have to upload manually.