The short answer is my most common answer: it depends.
It depends on who is providing the service and how sensitive you feel your documents are.
There are good services and bad services. Fortunately, there are also alternatives.
Who do you trust?
The very short version is that if it’s a company you’ve never heard of, you might want to do some research before blindly uploading your sensitive documents.
One way to start might be to do a “whois” lookup on the domain on which the service is provided. The service I tend to use is whois.domaintools.com. If you were considering using a service provided at somerandomservice.com, you might look that up first to see who’s behind it.
That may be enough to make you feel comfortable, or it may be information to use for additional online research on the company or owner.
If, of course, you recognize the company involved, then no research is needed. You simply need to answer the question, “Do I trust them?”
If the answer is yes, carry on. If the answer is no, you know to look for alternatives.
One example: Google
One service that provides the specific function you asked about is Google. You can upload a Word document to Google Drive and convert it there.
While it’s intended that you can then edit the file using Google Docs, there’s nothing that says you must. You can save the document to any of several different formats, including PDF.
Do it offline
Another way to protect yourself, should you feel at all uncomfortable with uploading your document, is to look for a solution that runs on your PC instead.
Assuming your convert-to-PDF scenario, there are a couple of options:
- Microsoft Office installed on your computer includes “Save as PDF”.
- Free Office alternatives like LibreOffice and OpenOffice can read your Word documents and save as PDF.
Depending on the software you have installed on your system, it’s possible you have additional options as well. Be sure to look for both “Save” and “Export” options in any programs you have that can open a Word document.
As you can see, Word to PDF is a common scenario with many options available. If you’re faced with some other kind of document conversion, things get more difficult.
Depending on your need, you may have tools on your machine already. Those are likely the safest approach, as they’re least likely to share your documents with others.
You may find online conversion utilities from companies you know and trust, like Google, Microsoft, or someone else. If so, then your problem is solved.
But it’s also possible for more obscure conversions that you’ll find options from companies you’ve never heard of. When that happens, the only advice I can give is to do the research and weigh the risks. In general, my sense is that the risk is very low, but depending on the sensitivity of the documents you need converted, even that may be too much.