In GTA Online to perform the Casino Heist you need to purchase an arcade. But not only that, you actually need to be a CEO or VIP to be able to access some of the planning and scouting features of the heist.
If you’ve been playing GTA Online all along, this shouldn’t be an issue. You can become the CEO or President of an MC by simply purchasing a property like an Office, Clubhouse, or Nightclub. Unfortunately, the arcade itself doesn’t allow you to simply register so as this so you’ll need to have one of these other properties.
If you’re short on cash, the cheapest way to go about it is to just purchase a Motorcycle Club, register as the President and you will then have access to all of the planning tools at the Arcade that you’ve purchased to plot out the Casino Heist.
Once you have the second property it will depend on what it is whether you will register as the CEO or President, but this can be done by opening your phone and then heading into the Securo Serv section to register.