Do I need identical servers for load balancing?

I am new to using AWS and web hosting in general. Let’s say I currently have a single server running a website, and the traffic starts to grow to a point I need to use load balancing. Assuming my current server is running on an EC2 instance with Ubuntu, and an Apache server with all the website files inside the /var/www/ folder. If I want to add load balancing, do I need to create an EC2 instance with the same website files copied to it? Or I just need to create an empty EC2 instance and the rest is done automatically? A bit confused as to how it would work.