How to transfer contacts from iPhone to PC?
You can use one of the free apps (e.g. My Contacts Backup) on the AppStore to export all of your contacts and Mail it to your e-Mail account or save it to Dropbox etc. 

Another way is, if you have your Contacts on iCloud. SignIn on icloud.com navigate to Contacts - Press cmd+A or ctrl+A on Windows. The in the corner left ist a Gear Symbol - and select Export vCard