Most PDF problems are avoidable. After years of sending and receiving documents professionally, the same mistakes come up again and again — from files that are too large to open on a mobile device, to contracts shared without any password protection. Here are the five most common PDF mistakes and how to fix every one of them.
Mistake 1: Sending a PDF that is too large to open on mobile
A 50 MB PDF that opens fine on your laptop can be completely unusable for a client trying to open it on a phone with limited storage. Email clients often refuse to download large attachments over a mobile connection, and some preview tools stall or crash entirely.
How to fix it: Before sending any PDF, ask yourself whether the recipient might open it on mobile. If yes, run it through the Compress PDF tool first. For most documents, compression reduces the file by 30–60% with no visible quality loss. Target a file size under 5 MB for email attachments and under 2 MB for anything that will be viewed on a phone.
Mistake 2: Sharing sensitive documents without password protection
Contracts, invoices, salary information, ID documents, and medical records get emailed without any protection every day. If that email is forwarded, if the recipient's account is compromised, or if the file is saved somewhere accessible, the information is exposed.
How to fix it: Take 30 seconds to password-protect sensitive PDFs before sending them. Use the Protect PDF tool, set a strong password, and share the password through a separate channel (not the same email). For internal documents you want to brand but not lock, add a watermark with the Watermark PDF tool instead.
Mistake 3: Sending pages in the wrong order
This happens constantly with merged documents — you combine files in a hurry and realise afterwards that the appendix ended up before the main report, or the signature page is on page 2 instead of the last page. The recipient has to scroll back and forth to make sense of it, which looks unprofessional and creates confusion in review meetings.
How to fix it: Always scroll through the final merged PDF before sending. If the order is wrong, use the Reorder Pages tool to drag pages into the correct sequence. It takes less than a minute and makes the document immediately more readable.
Mistake 4: Forgetting page numbers on long documents
A 30-page proposal without page numbers is hard to discuss in a meeting. When someone says "look at the section on pricing", the other person has no reference point. Page numbers are basic document etiquette — and surprisingly easy to forget when you are exporting from Word, Google Docs, or assembling files from different sources.
How to fix it: Use the Add Page Numbers tool to stamp page numbers onto any PDF after the fact. You can choose the position (bottom centre, bottom right, top right, etc.), the format (1, 2, 3 or Page 1, Page 2 or 1 of 12), and the starting number.
Mistake 5: Using the wrong title and metadata
When you export a PDF from Word or Google Docs, the file's internal metadata often contains the wrong title — your name, the document template name, or a generic "Untitled" tag. This metadata appears in document viewers, search results, and screen readers. Sending a client a proposal with internal metadata that says "Draft Template v2 — DO NOT SEND" undermines your professionalism.
How to fix it: Use the Edit Metadata tool to set the correct title, author, and subject before sending any important document. It takes 30 seconds and ensures that what the recipient sees in their document viewer matches what you intended.
All five fixes take under a minute each and are completely free. Build these habits and your documents will always arrive in the right shape.