MonoBehaviour.Invoke

Description

Invokes the method methodName in time seconds.

If time is set to 0, the method is invoked at the next Update cycle. In this case, it's better to call the function directly.

For better performance and maintability, use Coroutines instead.

using UnityEngine;
using System.Collections.Generic;

public class ExampleScript : MonoBehaviour
{
    // Launches a projectile in 2 seconds

    Rigidbody projectile;

    void Start()
    {
        Invoke("LaunchProjectile", 2.0f);
    }

    void LaunchProjectile()
    {
        Rigidbody instance = Instantiate(projectile);
        instance.velocity = Random.insideUnitSphere * 5.0f;
    }
}