There's lots on https://aws.amazon.com/vpc/, and talks on youtube (https://www.youtube.com/watch?time_continue=4&v=3qln2u1Vr2E is a fav). But the TLDR is this: VPC stands for "Virtual Private Cloud" and it gives you your own virtual data center on AWS. You get a private network that uses whatever IP range you'd like, and you can connect to it privately via VPN or Direct Connect (physical links). You can also connect it to the internet with Elastic IP Addresses.

VPCs are free and you can create and edit them programmatically (add subnets, change routes, manage ACLs and security groups) - so they're a useful way to manage an environment of things like EC2 instances, containers, Elastic Load Balancers, RDS databases, Lambda functions, and more, without needing to worry as much about them being exposed to things you don't control.

With this latest PrivateLink feature, it's now possible to offer services between VPCs. So you can build a service in its own VPC, and map into other ones, securely.