ApiManager.swift

import UIKit   

    struct RequestType {
      static let  POST = "POST"
      static let  GET = "GET"
    }

    enum HtttpType: String {
      case POST = "POST"
      case GET  = "GET"
    }

    class APIManager: NSObject {

      static let sharedInstance: APIManager = {

        let instance = APIManager()
        return instance
      }()
        // First Method

          public func requestApiWithDictParam(dictParam: Dictionary<String,Any>, apiName: String,requestType: String, isAddCookie: Bool, completionHendler:@escaping (_ response:Dictionary<String,AnyObject>?, _ error: NSError?, _ success: Bool)-> Void) {

            var apiUrl = “” // Your api url
            apiUrl =  apiUrl.appendingFormat("%@", apiName)
            let config = URLSessionConfiguration.default
            let session = URLSession(configuration: config)
            let url = URL(string: apiUrl)!
            let HTTPHeaderField_ContentType  = "Content-Type"
            let ContentType_ApplicationJson  = "application/json"
            var request = URLRequest.init(url: url)

            request.timeoutInterval = 60.0
            request.cachePolicy = URLRequest.CachePolicy.reloadIgnoringLocalCacheData
            request.addValue(ContentType_ApplicationJson, forHTTPHeaderField: HTTPHeaderField_ContentType)
            request.httpMethod = requestType

            print(apiUrl)
            print(dictParam)

            let dataTask = session.dataTask(with: request) { (data, response, error) in

              if error != nil   {
                completionHendler(nil, error as NSError?, false)
              } do {
                let resultJson = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:AnyObject]
                print("Request API = ", apiUrl)
                print("API Response = ",resultJson ?? "")
                completionHendler(resultJson, nil, true)

              } catch {
                completionHendler(nil, error as NSError?, false)
              }
            }
            dataTask.resume()
          }

           // Second Method
           public func requestApiWithUrlString(param: String, apiName: String,requestType: String, isAddCookie: Bool, completionHendler:@escaping (_ response:Dictionary<String,AnyObject>?, _ error: NSError?, _ success: Bool)-> Void ) {
                var apiUrl = "" // Your api url
                let config = URLSessionConfiguration.default
                let session = URLSession(configuration: config)            
                var request: URLRequest?

                if requestType == "GET" {

                  apiUrl =  String(format: "%@%@&%@", YourAppBaseUrl,apiName,param)
                  apiUrl = apiUrl.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
                  print("URL=",apiUrl)

                  let url = URL(string: apiUrl)!
                  request = URLRequest.init(url: url)
                  request?.httpMethod = "GET"

                } else {

                  apiUrl =  String(format: "%@%@", YourAppBaseUrl,apiName)
                  apiUrl = apiUrl.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
                  print("URL=",apiUrl)

                  let bodyParameterData = param.data(using: .utf8)
                  let url = URL(string: apiUrl)!

                  request = URLRequest(url: url)
                  request?.httpBody = bodyParameterData
                  request?.httpMethod = "POST"
                }

                request?.timeoutInterval = 60.0
                request?.cachePolicy = URLRequest.CachePolicy.reloadIgnoringLocalCacheData
                request?.httpShouldHandleCookies = true

                let dataTask = session.dataTask(with: request!) { (data, response, error) in

                  if error != nil {
                    completionHendler(nil, error as NSError?, false)
                  } do {
                    if data != nil  {
                      let resultJson = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:AnyObject]

                      print("Request API = ", apiUrl)
                      print("API Response = ",resultJson ?? "")
                      completionHendler(resultJson, nil, true) 
                    } else  {
                      completionHendler(nil, error as NSError?, false)
                    }
                  } catch {
                    completionHendler(nil, error as NSError?, false)
                  }
                }
                dataTask.resume()
              }
    }

    // Here is example of calling Post API from any class

     let bodyParameters = String(format: "appid=%@&appversion=%@","1","1")
            APIManager.sharedInstance.requestApiWithUrlString(param: bodyParameters, apiName: "PASS_API_NAME", requestType: HtttpType.POST.rawValue, isAddCookie: false) { (dictResponse, error, success) in

                if success {
                    if let dictMessage = dictResponse?["message"] as? Dictionary<String, AnyObject> {
                // do you work
                    }

                }  else {
                    print("Something went wrong...")
                }
            }
        }


/// Or just use simple function 

func dataRequest() {
    let urlToRequest = "" // Your API url

    let url = URL(string: urlToRequest)!
    let session4 = URLSession.shared
    let request = NSMutableURLRequest(url: url)
    request.httpMethod = "POST"
    request.cachePolicy = NSURLRequest.CachePolicy.reloadIgnoringCacheData
    let paramString = "data=Hello"
    request.httpBody = paramString.data(using: String.Encoding.utf8)
    let task = session4.dataTask(with: request as URLRequest) { (data, response, error) in
      guard let _: Data = data, let _: URLResponse = response, error == nil else {
        print("*****error")
        return
      }
      if let dataString = NSString(data: data!, encoding: String.Encoding.utf8.rawValue) {
          print("****Data: \(dataString)") //JSONSerialization
      }
    }
    task.resume()
  }