Practical, tested guidance for everyday PDF jobs — including what to do when a conversion does not go as expected.
How to reduce PDF file size
The biggest factor in PDF size is almost always images. A scanned page saved at 300 DPI can be ten times larger than the same page at 150 DPI, and a photo inserted at full camera resolution dwarfs the text around it. Start by checking where the size comes from: a PDF that is mostly text should already be small, while a scanned document is really a set of pictures. Practical steps that work: use Compress PDF here for a quick re-save and compare the before/after sizes; if the result is still too big, re-export the source document with images at 150 DPI instead of 300 DPI; and avoid embedding the same large logo on every page at full resolution. If a form or upload limit is, say, 5 MB, aim for comfortably below it — a file that is exactly at the limit may still be rejected after the uploader adds its own overhead. Do not delete pages you need just to hit a size target; extract or split instead, and keep the original.
How to combine PDF documents
Combining PDFs is usually about order: the reader should meet the cover letter first, then the main document, then the appendices. Gather the files, name them in the order you want if that helps, and use Merge PDF to arrange them with the up/down controls before processing — the output follows that list exactly. Check the merged result before sending it: open it, skim the first page of each section, and confirm nothing is upside down (rotate first if needed) and no section is duplicated. If you only need part of a document, extract those pages first rather than merging a whole file and apologising for the extra pages. Merged PDFs keep each page's original size and orientation, but bookmarks and form fields from the originals are not carried over, so do not rely on them in the combined file.
How to convert images into a PDF
Turning images into a PDF is the reliable way to send scans, receipts or photos as one document that looks the same everywhere. Use JPG to PDF, add up to 20 JPG or PNG images, and set the order before processing — the first image becomes the first page. A few habits make the result much better: photograph or scan pages straight on, in good light, with the page filling the frame; keep portrait pages portrait and landscape pages landscape, because each page follows its own image; and check the finished PDF page by page, since a single sideways photo is easy to miss. Note that the result is pictures, not selectable text — if you need searchable text, you need OCR, which this tool does not claim to do. For long documents, split the images into batches rather than forcing everything into one enormous file.
How to protect a PDF with a password — and troubleshoot failed conversions
Password protection only helps if the password is strong and stored safely. Choose a password you do not reuse elsewhere, of at least 4 characters (longer is better), and keep it somewhere you will find it — a forgotten PDF password cannot be recovered by us, because it is never stored. Send the password to the recipient by a different channel than the file itself, and test that the protected file opens before you send it. When any conversion fails, work through the common causes in order: check the file type (DOCX only for Word to PDF, PDF for the rest), check the size limit (50 MB for PDFs, 10 MB for Word), try opening the file on your own device to rule out damage, and if it is password-protected, remove the password first — browser tools cannot process protected PDFs. If a Word document converts with shifted formatting, simplify the cause: unusual fonts, tracked changes and complex tables are the usual culprits, and re-exporting with standard fonts usually fixes it.