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PDF 指南 与操作教程

Edit any PDF onlinewithout uploading it

Change text in its own font, sign a page and type on a form, right in your browser - no detour through Word, and your file never leaves your computer.

压缩 PDF 指南

在不毁掉文件的前提下把 PDF 变小：压缩会改变什么、该选哪个级别，以及如何压到上传限制以内。

A PDF document with a dashed measuring frame around a small solid block, standing for a file squeezed to fit a size limit
压缩 PDF

PDF under 100 KB

How to Compress a PDF to 100 KB (or Any Size a Form Demands)

A visa portal wants 100 KB and your scan is 1.8 MB. Here is how to find out what is making the file heavy, which level to pick, and what to do when Smaller still is not small enough.

10 min read阅读指南
A PDF document with a red warning triangle over it, marking a file that will not send as an email attachment
压缩 PDF

Too big to email

Your PDF Is Too Big to Email: The Limits and What Actually Works

The send button failed, or the message bounced an hour later. Here are the real attachment limits at Gmail, Outlook and a typical company server, why your file gets a third bigger in transit, and the four ways to get the document there.

11 min read阅读指南
Two stacked sheets of paper under a large magnifying glass, standing for a scanner looking at a page as a picture
压缩 PDF

Why scans are large

Why Scanned PDFs Are So Large, and How to Shrink Them

Ten typed pages are 200 KB. Ten scanned pages are 40 MB, and they say the same thing. The difference is that a scan is a photograph of a page rather than the words on it. Here is the arithmetic, and what to do about it.

11 min read阅读指南
A PDF page squeezed between two arrows beside a badge reading 78 percent smaller
压缩 PDF

How to compress a PDF

How to Compress a PDF: Reduce File Size Without Losing Quality

A 12 MB PDF that will not send is almost always a few oversized images in a wrapper. Here is what compression actually changes, which level to pick, and how to get under a limit without turning your text to mush.

10 min read阅读指南
A PDF page squeezed by two arrows beside a panel reading 78 percent smaller
压缩 PDF

Compress without losing quality

How to compress a PDF without losing quality

Choosing the right compression level matters for email attachments, web uploads, and print-ready documents.

2 min read阅读指南

每个工具都有一篇指南

每个工具做什么、什么时候用它，以及上传任何文件前值得了解的设置。