The best way to protect a PDF on any computer or phone is through an online service called TinyWow. TinyWow is your go-to place for all PDF-related functions. To protect your PDF with a password using the tool, follow these steps: 1. On your browser, go to TinyWow’s PDF protect page. 2. Search for “Protect PDF” and select the first result that shows up. 3. Click the “Upload from PC or Mobile” button to upload the PDF file you want to protect with a password. 4. Enter a suitable password for your document and press the “Protect” button. 5. Wait a few seconds for the processing to finish. 6. Once the file is ready, hit the “Download” button to download the file you’ve just protected to your device’s local storage. Please note that the website stores your processed files for an hour from upload time. Therefore, download your file immediately if it’s already encrypted; otherwise, you risk repeating the process. Also, if you run into any issues, let’s say, you encounter an error while processing the file; trying a different browser should resolve the issue.