How can I use a navmesh with keyboard input to move an object?

     float horInput = Input.GetAxis("Horizontal");
     float verInput = Input.GetAxis("Vertical");
     Vector3 movement = new Vector3(horInput, 0f, verInput);

     Vector3 moveDestination = transform.position + movement;

     GetComponent<NavMeshAgent>().destination = moveDestination;

Put this code in the Update function.

We are basically getting the input. Storing it in Vector 3. Calculating the position to move and store it as a Vector 3. And updating the navmeshagent's destination.