When creating a new Virtual Network in Azure, you might have noticed that the site-to-site connectivity option is missing, while the point-to-site connectivity is ready for activation.

The most probable reason for this is that there is no Local Networks configured in the subscription where you created the new Virtual Network.

Try browsing to New, Network Services, Virtual Network, All Local Network, and create a new one for the subscription where you need it. Then go back to the Virtual Network Configuration tab and you should see the create a site-to-site connectivity option.