Language Learning Models (LLMs) have revolutionized the way we interact with PDFs, enabling us to chat with them and extract valuable information. With the power of LLMs, individuals and businesses can automate repetitive tasks, improve productivity, and make their lives easier. The technology behind LLMs is based on transformer-based deep learning models that utilize attention mechanisms to understand context within language. OpenAI's GPT-4, GPT-3.5, Claude LLM v1, Microsoft T5, LLaMA, StableLM, and Dolly are some of the most advanced LLMs available, each with their strengths and weaknesses. When choosing a GPT model, it's essential to consider your use case and specific requirements, as each model has its pros and cons. Ultimately, LLMs have the potential to transform and automate any document-driven task, making them an exciting development in the field of natural language processing.