PDFs are where the sensitive stuff lives: tax statements, signed contracts, bank reports. So the worst place to handle them is a "merge PDF free" site that asks you to upload the documents first. If you're shuffling personal or client paperwork, an upload is exactly the risk you don't need.
Keep it on your machine. The PDF Merge tool stacks several PDFs into one, in the order you set, entirely in the browser. Reorder or drop a file, then merge again — the combined document downloads to you and nothing was ever sent anywhere.
The reverse job is just as common. The PDF Split tool turns one PDF into one small file per page, so you can pull out the three pages you actually need and send only those. No need to share the whole deck.
When a merged or scanned file is too heavy to email, the PDF Compress tool does an honest, lossless re-save using object streams. It won't magically shrink a photo-heavy report — that would mean re-encoding images and losing quality — but it trims real, safe weight with no fidelity loss.
Why local? Because a PDF about your finances has no business sitting on a stranger's server while a tool processes it. Doing it in-browser means the document never leaves the tab.
Quick path: merge what you need into one file, split out the pages you want to share, then run a light compress before emailing. Private end to end.