LangChain is a framework that enables the creation of applications using large language models (LLMs) like GPT. It provides functionalities such as token management and context management, allowing users to build with the CVP Framework. The two core LangChain functionalities for LLMs are data-awareness and agency. One primary use case is querying text data, which can be done using documents, vector stores, or GPT interactions. In this tutorial, we covered how to interact with GPT using LangChain and queried a document for semantic meaning using LangChain with a vector store.