An EC2 instance is a virtual server in the cloud provided by Amazon Web Services (AWS) that allows users to run applications and operating systems virtually without any physical need of the hardware.
There are three types:
1.General Purpose Instances.
2.Compute Optimized Instances.
3.Memory-Optimized Instances.
Let’s see each of them in brief
1.General Purpose Instances
General Purpose instances are instances that provide a combination of compute (CPU), memory (RAM), and networking resources, making them suitable for a wide range applications. These include series such as t2.micro,t3.micro,m5.large,m5.2xlarge.
2.Compute Optimized Instances Compute Optimized instances instances that are designed to deliver high-performance processors and greater CPU capacity, making them ideal for compute-intensive applications(CPU).These also include series like c5.large,c5.2xlarge.
3.Memory-Optimized Instances
Memory Optimized instances are instances designed to provide large amounts of RAM, for fast performance and for memory-intensive workloads. This also include series like r5.large,r5.2xlarge.
A Name tag is used to provide a name or an identity for an EC2 instance is known as a name tag. It is useful for easy identification and management.

AMI stands for Amazon Machine Image is a template which contains an operating system, software, and settings required to launch an EC2 instance.
