how do I make the mesh renderer script create smooth movement in realtime?

I created a mesh renderer and thought it would be a fun idea to have randomized land for my low poly game(NOPE) so i scraped using it and was about to chuck it out. I realized i needed water but unfortunately I dont know how to make it so that the mesh renderer script will create movement in real time. can anyone help me out with this? I added comments this time.

[RequireComponent(typeof(MeshFilter))] public class MeshGen : MonoBehaviour {

 Mesh mesh;

 Vector3[] vertices;
 int[] triangles;

 public int xSize = 600;
 public int zSize = 600;


 void Start()
 {
     // creates mesh components needed
     mesh = new Mesh();
     GetComponent<MeshFilter>().mesh = mesh;
     
     CreateShape();
     UpdateMesh();
     GetComponent<MeshCollider>().sharedMesh = mesh;
 }
 void CreateShape()
 {
     // creates the vertices
     vertices = new Vector3[(xSize + 1) * (zSize + 1)];
  
     for (int i = 0, z = 0; z <= zSize; z++)
     {
         for (int x = 0; x <= xSize; x++)
         {
             // this is the part that I think needs to be updated in realtime so that movement can be seen in the game
             // this part creates the slops and divots.
             float y = Mathf.PerlinNoise(x * 0.12f, z * 0.12f) * 1f;
             vertices[i] = new Vector3(x, y, z);
             i++;
         }
     }
     // creates the triangles that attaches to the vertices
     triangles = new int[xSize * zSize * 6];

     int vert = 0;
     int tri = 0;

     for (int z = 0; z < zSize; z++)
     {
         for (int x = 0; x < zSize; x++)
         {
             triangles[tri + 0] = vert + 0;
             triangles[tri + 1] = vert + xSize + 1;
             triangles[tri + 2] = vert + 1;
             triangles[tri + 3] = vert + 1;
             triangles[tri + 4] = vert + xSize + 1;
             triangles[tri + 5] = vert + xSize + 2;


             vert++;
             tri += 6;
         }
         vert++;
     }

 }
 void UpdateMesh()
 {
     mesh.Clear();

     mesh.vertices = vertices;
     mesh.triangles = triangles;

     mesh.RecalculateNormals();
 }

}