Real Simple 2D Movement

Player.cs

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

public class Player : MonoBehaviour
{
    [SerializeField] private float speed;        //Controls player speed, this can be adjusted
    private Vector3 playerPos;                   //Sets player position

    // Start is called before the first frame update
    void Start()
    {
        playerPos = Vector3.zero;                //Sets PlayerPos to zero in the world space
        transform.position = playerPos;          //Sets the Player's transform to PlayerPos
    }

    // Update is called once per frame
    void Update()
    {
        //As players move either WASD or the arrow keys (or whatever keys are defined by Unity's input system) every frame, playerPos is updated
        playerPos = new Vector3(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical"));
        
        //Uses transform.Translate to communicate to Player GameObject to move where PlayerPos is
        //Time.delta simply translate this movement into real-time seconds instead of frames
        //The speed variable dictates how fast the Player moves over time
        transform.Translate(playerPos * Time.deltaTime * speed);                              
    }

}