connecting HC12 module to attiny85

Hi everyone.
i have difficulty programming an attiny85 that collects data from a dht22 sensor and transmits it using a HC12 module. I need to send temperature and humidity data from the dht22 to an arduino mega using HC12 modules. Kindly advise.
The code for TX is shown below:

#include <SoftwareSerial.h>
//#include<avr/io.h>
//#include<util/delay.h>
#include <dht.h>   
dht DHT;
#define DHT22_PIN 4

const byte HC12Rxdpin=1;
const byte HC12Txdpin=0;

String HC12ReadBuffer;
boolean HC12End=false;
SoftwareSerial HC12(HC12Txdpin,HC12Rxdpin);


//byte currentNodeAddr[6]="1Node";
float h=0;
float t=0;
int transmit_t=0;
int transmit_h=0;
int transmit_data=0;
int led=3;

void setup() {
  HC12ReadBuffer.reserve(64);
  pinMode(1, OUTPUT);
pinMode(0, INPUT);
pinMode(4, INPUT);
pinMode(3, OUTPUT);
HC12.begin(9600);
}

void loop() {
  delay(2000);
  uint32_t start= micros();
 int chk= DHT.read22(DHT22_PIN);
  uint32_t stop= micros();
  h=DHT.humidity;
  t=DHT.temperature;
  transmit_h=100*(int)h;
  transmit_t=(int)t;
  transmit_data=transmit_h+transmit_t;
  HC12.print(transmit_data);
  delay(2000);
}

The RX code:

#include <SoftwareSerial.h>;

const byte HC12RxdPin = 11;                  // Recieve Pin on HC12
const byte HC12TxdPin = 10;                  // Transmit Pin on HC12

SoftwareSerial HC12(HC12TxdPin,HC12RxdPin); // Create Software Serial Port

void setup() {
  Serial.begin(9600);                       // Open serial port to computer
  HC12.begin(9600);                         // Open serial port to HC12
}

void loop() {
  if(HC12.available()){                     // If Arduino's HC12 rx buffer has data
    Serial.write(HC12.read());              // Send the data to the computer
    }
  if(Serial.available()){                   // If Arduino's computer rx buffer has data
    HC12.write(Serial.read());              // Send that data to serial
  }
}

What Arduino core software are you using to program the ATTiny85 because there a specialties eg with softwareSerial and pin usage etc.?
Since the receiver is an Arduino Mega, you almost certainly don't want to use softwareSerial there.
Can you provide a link to the tutorial you are following for the HC12 ?

The core software i'm using is attiny by David A Mellis version 1.0.2

HC12 module tutorial link: https://www.allaboutcircuits.com/projects/understanding-and-implementing-the-hc-12-wireless-transceiver-module/

I can't say much about it because I have not yet experimented with this device, however this appears to be incorrect:

SoftwareSerial HC12(HC12Txdpin,HC12Rxdpin);

The parameters for sofwareSerial have this order:

SoftwareSerial mySerial(myRX, myTX); // RX, TX

I guess you can start on the Mega where you have multiple hardware serial ports and see if you can send AT commands to the device there, just to check that you can talk to it using the second example sketch in your tutorial.