Database
db={"Agencies":[{"name":"tcs","id":"1","AgencyUsers":[{"UserName":"ABC","Code":"ABC40","Link":"http.ios.com","TotalDownloads":0},{"UserName":"xyz","Code":"xyz20","Link":"http.ios.com","TotalDownloads":0}]}]}
Query
db.Agencies.update({"AgencyUsers.Code":"ABC40"},{$inc:{"AgencyUsers.$[agencyUser].TotalDownloads":1}},{arrayFilters:[{"agencyUser.Code":"ABC40"}]})