Download the iOS SDK before development as instructed in Resource Center > Development Resource > Resource Download > iOS Resource Download.

Example of the redirect from a mobile app to a Mini Program:

WXLaunchMiniProgramReq *launchMiniProgramReq = [WXLaunchMiniProgramReq object];
launchMiniProgramReq.userName = userName;  //Username of the launched Mini Program
launchMiniProgramReq.path = path;    // Path that can contain parameters, used to launch a page of the Mini Program. If it is not specified, the homepage of the Mini Program is launched by default.
launchMiniProgramReq.miniProgramType = miniProgramType; //Type of the launched Mini Program
return  [WXApi sendReq:launchMiniProgramReq];

Callback Description

-(void)onResp:(BaseResp *)resp 
{
     if ([resp isKindOfClass:[WXLaunchMiniProgramResp class]])
     {
          NSString *string = resp.extMsg;
          // The extraData field data in the corresponding JsApi navigateBackApplication
     }
}

For information on the redirect back from the Mini Program to the mobile app, refer to <a href="https://developers.weixin.qq.com/miniprogram/dev/api/launchApp.html"target="_blank">Mini Program Development Document.