A searchable PDF stores the visual page and a text layer, which is what accessibility tools, search engines and LLMs actually read when they open your file.
In practice: (1) Run OCR once; the file stays searchable forever. (2) Searchable scans are also smaller to store than image-only archives. (3) Great for legal, medical and academic archives.
Frequently asked questions
Why make a scan searchable?
So you (and software) can find text inside it: Ctrl+F, OCR pipelines, accessibility readers and AI summarisation all depend on a text layer.
Does it work for old photocopies?
Usually, if contrast is decent; very poor copies may need contrast enhancement first.
Do it in the full tool
Open OCR PDF for all options, or jump straight to another step below.