Question Answering (QA) systems automatically answer natural language questions by retrieving relevant information and generating or extracting answers. Modern QA systems combine three components: (1) retrieval—finding relevant documents/passages, (2) reading comprehension—locating or generating answers within context, and (3) ranking—scoring and selecting the best answer. Powered by transformers (BERT, T5, GPT) and retrieval engines, QA systems enable chatbots, customer support automation, search, and knowledge base automation. QA is critical infrastructure for modern AI assistants, search engines, and knowledge management. Companies building customer service bots, documentation search, and internal knowledge bases need QA expertise. The convergence of LLMs and retrieval (RAG) makes QA increasingly central; specialists command premiums and lead high-impact projects.