You encode your document with some kind of embedding, eg HuggingFace Sentence Transformers: https://www.sbert.net/ https://www.sbert.net/ (probably most commonl

You encode your document with some kind of embedding, eg HuggingFace Sentence Transformers: https://www.sbert.net/ https://www.sbert.net/ (probably most commonly used) or OpenAI Embeddings: https://platform.openai.com/docs/guides/embeddings/what-are-embeddings https://platform.openai.com/docs/guides/embeddings/what-are-... and then use a vector database (Elastic, Postgres, FAISS or whatever) to do a similarity search.