How can I sprint with left shift? Character Controller

Questions & Answers
1

Hello everyone, I want to make my character sprint when left shift is pressed. I tried much solutions from the internet and nothing worked with my character controller. I only need to know how to speed up the player.

Thank you

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerMovement : MonoBehaviour
{

    public CharacterController controller;

    public float speed = 12f;
    public float gravity = -9.81f;
    public float jumpHeight = 3f;

    public Transform groundCheck;
    public float groundDistance = 0.4f;
    public LayerMask groundMask;

    Vector3 velocity;
    bool isGrounded;
  

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {

        isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);

        if(isGrounded && velocity.y < 0)
        {
            velocity.y = -2f;
        }

    

        float x = Input.GetAxis("Horizontal");
        float z = Input.GetAxis("Vertical");

        Vector3 move = transform.right * x + transform.forward * z;

        controller.Move(move * speed * Time.deltaTime);
    

        if(Input.GetButtonDown("Jump") && isGrounded)
        {
            velocity.y = Mathf.Sqrt(jumpHeight * -2 * gravity);
        }

       

        velocity.y += gravity * Time.deltaTime;

        controller.Move(velocity * Time.deltaTime);
    }
}
2

Well, You Could Change The Speed Every time You Press Shift like this :
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

 public class PlayerMovement : MonoBehaviour
 {
 
     public CharacterController controller;

     public float sprintSpeed = 15f;
     public float speed = 12f;
     public float gravity = -9.81f;
     public float jumpHeight = 3f;
 
     public Transform groundCheck;
     public float groundDistance = 0.4f;
     public LayerMask groundMask;
 
     Vector3 velocity;
     bool isGrounded;
   
 
     // Start is called before the first frame update
     void Start()
     {
         
     }
 
     // Update is called once per frame
     void Update()
     {
 
         isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);
 
         if(isGrounded && velocity.y < 0)
         {
             velocity.y = -2f;
         }
 
     
 
         float x = Input.GetAxis("Horizontal");
         float z = Input.GetAxis("Vertical");
 
         Vector3 move = transform.right * x + transform.forward * z;
 
         controller.Move(move * speed * Time.deltaTime);

        if (Input.GetKey(KeyCode.LeftShift))
        {
             speed = sprintSpeed;
        }else
        {  
            speed = 12f;
        }
     
 
         if(Input.GetButtonDown("Jump") && isGrounded)
         {
             velocity.y = Mathf.Sqrt(jumpHeight * -2 * gravity);
         }
 
        
 
         velocity.y += gravity * Time.deltaTime;
 
         controller.Move(velocity * Time.deltaTime);
     }
 }

Hope It Works!