How i can use synchronize in IOS apiv2

I recommend reading through the readme file for the API v2 Objective-C SDK to get started. That covers the basics of using the SDK. You can also refer to the sample app.

The SDK offers methods for listing, downloading, and uploading files, among other operations. The SDK doesn't do syncing automatically for you, but you can use these methods to implement whatever syncing functionality you need in your app.