WukongPDF Blog

PDF tips, tutorials, and product updates.

How to Remove a Watermark From a PDF
Whether you can remove a watermark from a PDF depends on how the watermark was added.
Why Is My PDF Sideways?
A sideways PDF is almost always fixable in under a minute. The page rotation is stored in the file and can be changed without affecting the content.
How to Convert PDF to PNG
Converting a PDF to PNG turns each page into a separate image file. It's useful when you need to embed a PDF page into a presentation, share a single...
How to Make a PDF Fillable for Free
Creating a fillable PDF — one where recipients can click fields and type directly instead of printing and handwriting — used to require Acrobat Pro.
Can You Change the Page Size of a PDF?
Changing the page size of an existing PDF is possible, but it works differently depending on what you actually need.
How to Convert a Photo to PDF on Android
Android doesn't have a single built-in way to convert photos to PDF the way iPhone does — the experience varies by manufacturer and Android version.
Why Does My PDF Have a Gray Background?
A gray background on a PDF page is usually one of three things: it was designed that way intentionally, it's a viewer display setting, or it came...
How to Add Text to a PDF Without Acrobat
Adding text to a PDF without Acrobat is entirely possible — the question is what kind of text you're adding.
What Happens When You Flatten a PDF?
Flattening a PDF merges all of its separate layers into a single static page.
What Is the Best Way to Send a Large PDF File?
Email attachment limits — typically 10-25MB depending on the provider — catch people off guard more often than they should.
How to Protect a PDF From Being Copied
Protecting a PDF from being copied is something you can set up in a few minutes, but it's worth being clear-eyed about what these protections...
How to Combine PDF Files Without Adobe
Combining PDF files without Adobe is straightforward — Preview on Mac has done it for years, and browser-based tools handle it on any platform.
Can You Convert Multiple Images to One PDF?
Combining multiple images into a single PDF is one of the more common everyday PDF tasks — packaging a set of photos, assembling a multi-page scan,...
Can You Password Protect a PDF for Free?
Password protecting a PDF doesn't require paid software. Both Mac and browser-based tools handle it for free, and the resulting protection is the...
How to Convert PDF to Word on Windows for Free
Windows doesn't have a built-in PDF-to-Word converter, but there are several free options that work well for most documents — no paid software...
How to Crop a PDF Page
Cropping a PDF page trims what's visible — removing unwanted margins, cutting off a header or footer, or isolating a specific section of a page.
Why Is My PDF Not Displaying Correctly?
When a PDF looks wrong — garbled text, missing images, strange colors, or content that just won't load — the cause is almost always one of three...
Why Does My PDF Not Print in Color?
A color PDF printing in black and white is almost always a printer setting issue rather than a problem with the file.
How to Add a Signature to a PDF on Mac
Adding a signature to a PDF on Mac requires nothing beyond Preview, which ships with every Mac.
Can You Convert a PDF to Google Docs?
Google Drive can open and convert PDFs to Google Docs format directly — no third-party tool needed.