Need to merge two PDFs, shrink a scan or add a password? A quick search turns up dozens of websites that will do it in the browser, often in less time than it takes to install anything. For a lot of tasks, that's a perfectly reasonable choice. For client documents, it's worth pausing on one question first: where does the file go while the work is being done?
This article doesn't argue that online tools are bad. It explains what actually changes between an online tool and software that runs on your own device, so you can decide document by document.
What happens when you use an online PDF tool
Most browser-based PDF tools follow the same pattern:
- You select a file, and your browser uploads a copy to the provider's servers.
- The servers process it: merge, compress, convert, encrypt.
- You download the result.
- The copies on the server, the one you sent and the one produced, are deleted at some point, according to the provider's own rules.
Some tools do part or all of the work inside the browser itself, without sending the file anywhere. From the outside, the two approaches can look identical. The only reliable way to know is the provider's own documentation.
The key point is step 1. The moment a file is uploaded, a copy of it exists outside your device, on infrastructure you don't control, governed by terms you may not have read. That isn't a sign of bad intent. It's simply how a server-side service works.
What to read before uploading a client document
If you do use an online tool for anything sensitive, its privacy policy and terms of service should answer a few concrete questions:
- Retention. How long are uploaded and processed files kept? Is deletion automatic, and after how long?
- Location. In which country are the servers? That can matter for data-protection rules that apply to you or your clients.
- Access. Who at the provider, or at its subcontractors, can access the files? Are they used for anything besides processing your request?
- Security. Are files encrypted in transit and on the server?
- Accounts and history. If you sign in, does the service keep a history of your documents?
If the answers are vague or missing, treat that as information too. And keep in mind that you're relying on the provider to do what its policy says; you can't verify it yourself.
What changes with local software
With software that processes files on your own computer or phone, the sequence is shorter: you open the file, the work happens on the device, the result is saved next to the original. No copy of the document is sent anywhere as part of the process.
That removes a whole category of questions. There's no retention period to check, because there's nothing retained elsewhere. There's no server location, because there's no server in the loop for the document. What remains is your own responsibility: keeping your device secure, backed up and up to date, which you already have to do since the documents live there anyway.
Local software has its own trade-offs, and it's fair to list them:
- It has to be installed, which takes longer than opening a web page and isn't always possible on a locked-down work computer.
- It depends on the platforms it supports. A tool that doesn't run on the device you have in hand isn't much help.
- It often requires a licence or subscription, where many online tools let you process a few files without paying.
- Your device does the work, so a very large batch uses your computer's resources.
When local really matters
For a restaurant menu, a public brochure or a document you'd happily post on your website, an online tool is fine. The calculation changes when the PDF contains information that belongs to someone else and that you've promised, or are required, to keep confidential:
- tax returns, payslips, bank statements and financial statements;
- contracts, engagement letters, court documents;
- medical or insurance records;
- identity documents and anything with dates of birth or account numbers.
For those documents, the question isn't whether a given online service is trustworthy. It's whether you need a copy to leave your device at all. If the work can be done locally, not uploading is the simplest answer, and the easiest one to explain to a client who asks how their documents are handled.
A simple rule of thumb many practices adopt: if you wouldn't email the document to a stranger, don't upload it to a service whose terms you haven't read. Then decide case by case.
An example
Picture Ortega & Lin, a fictional two-person accounting practice. For marketing flyers and public forms, they use whatever online tool is handy. For client files, they've set a rule: compressing, merging, cleaning metadata and protecting all happen on their own computers. When a client asks how their tax documents are handled, the answer is short: they stay on the firm's machines until they're sent, encrypted, to the client.
How PDF Protect Plus fits in
PDF Protect Plus was built for the second category. Documents are processed on your device, on Windows, macOS or Android. The app talks to our server only for account sign-in, licence checks and the subscription; your PDFs are not sent to it.
The local toolset covers the tasks people most often go online for:
- password protection with AES-256 encryption, alone or in batches of up to 200 PDFs with a different password per client;
- unlocking a protected PDF when you know its password;
- merging, splitting, reordering, rotating and compressing;
- watermarks and page numbers;
- metadata cleaning (the Info dictionary and XMP metadata);
- OCR in English and French on desktop, to make scans searchable.
Every result is saved as a new file, so the original stays untouched. More detail on what stays on the device is on the local processing page and in our privacy policy.
The short version
- Online tools are convenient and fine for non-sensitive documents.
- Uploading means a copy leaves your device; its fate depends on the provider's terms.
- Local software keeps the file on your device, in exchange for installing it.
- For client documents, local processing removes questions you'd otherwise have to answer.
To see how this works for a specific task, read how to merge PDF files without uploading them. You can also download PDF Protect Plus and try it on your own documents during the 7-day trial; plans are listed on the pricing page.