The document provides an introduction to large language model (LLM) customization, focusing on methods such as retrieval-augmented generation (RAG) and fine-tuning. It discusses how vector databases like Milvus can enable data injection for improved factual recall, and outlines various fine-tuning techniques for adapting LLMs to specific styles or domains. The content is aimed at developers interested in utilizing Zilliz's resources for LLM enhancements.