Last updated on
Jan 16, 2026
Lock large PDF files For Free
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Up to 100 MB for PDF and up to 25 MB for DOC, DOCX, RTF, PPT, PPTX, JPEG, PNG, JFIF, XLS, XLSX or TXT
Note: Integration described on this webpage may temporarily not be available.
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Create & edit PDFs
Generate new PDFs from scratch or transform existing documents into reusable templates. Type anywhere on a PDF, rewrite original PDF content, insert images or graphics, redact sensitive details, and highlight important information using an intuitive online editor.
Fill out & sign PDF forms
Say goodbye to error-prone manual hassles. Complete any PDF document electronically – even while on the go. Pre-fill multiple PDFs simultaneously or extract responses from completed forms with ease.
Organize & convert PDFs
Add, remove, or rearrange pages inside your PDFs in seconds. Create new documents by merging or splitting PDFs. Instantly convert edited files to various formats when you download or export them.
Collect data and approvals
Transform static documents into interactive fillable forms by dragging and dropping various types of fillable fields on your PDFs. Publish these forms on websites or share them via a direct link to capture data, collect signatures, and request payments.
Export documents with ease
Share, email, print, fax, or download edited documents in just a few clicks. Quickly export and import documents from popular cloud storage services like Google Drive, Box, and Dropbox.
Store documents safely
Store an unlimited number of documents and templates securely in the cloud and access them from any location or device. Add an extra level of protection to documents by locking them with a password, placing them in encrypted folders, or requesting user authentication.
Customer trust by the numbers
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average user rating
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Top-rated for ease of use
Create, edit, and fill out PDF documents faster with an intuitive UI that only takes minutes to master.
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What our customers say about pdfFiller
See for yourself by reading reviews on the most popular resources:
I worked fine for my needs of filling in a PDF file and saving it with data. I would like to see the ability to CREATE a fillable PDF file that I could distribute to others to fill out, save, and return to me.
2015-02-17
Pretty easy to use...so far.
The only thing that concerns me was I didn't realize I had to pay for this until I had finished filling out a complex form. How did i miss that information at the beginning?
2016-05-18
I needed fast, no nonsense access to CMS approved forms, HCFA1500 to be specific. This was fast, easy to use, and I can save my files to my pc. I can edit, print, e mail, fax, its great! I love it! I had questions on how to use certain edit features, I couldn't figure out, as I am not a computer "savy" person, I just get on, know what I have to do, and need it to work. The support team responded immediately to my questions and I knew I had 24-7 access to them which is important to me as I often work late at night. That is actually priceless. Great product at a great price w awesome customer support
2016-09-05
Overall the format is excellent -- the clearest, fastest and most accessible set of URL instructions I've ever used -- EXCEPT haven't yer succeeded in getting a doc e-signed! Maybe we were missing a step. The doc got e-sent to the signer, but all he ever got was the sample doc to fill out -- but it wouldn't let him fill it out. and just kept popping up the sample doc. Even tho ' it side we'd successfully down loaded the doc - but it appears it kept downloading the same sample doc and not the one I'd sent him to sign,
2018-10-02
Decent, though the affiliated linked program options which supposedly come with the upgrade purchase don't seem to work / or be actually as advertised.
2019-05-27
****** from PdfFiller is Excellent!I needed to cancel my service for the time being for financial reasons and they handled it kindly and seamlessly with no hassle. Should I need this type of service again, I will definitely be back. Would recommend PdfFIller to others. The service itself is intuitive and helped me easily provide my on boarding information for my new job.
2022-05-30
Lock Large PDF Files for Secure Document Management
Managing large PDF files often raises concerns about security and accessibility. Our 'Lock Large PDF Files' feature addresses these issues directly. It allows you to protect your important documents while ensuring that you and your team can access them when needed. This tool offers a simple way to keep your sensitive information safe from unauthorized access.
Key Features of Lock Large PDF Files
Secure password protection for sensitive documents
Control access by setting permissions for viewing and editing
Easy to use interface for locking and unlocking files
Batch processing for locking multiple files at once
Full integration with existing document management systems
Potential Use Cases and Benefits
Protect client contracts and agreements from unauthorized access
Safeguard confidential business reports during internal reviews
Ensure secure sharing of large PDFs in collaboration projects
Maintain compliance with data protection regulations
Increase trust with clients and partners by demonstrating document security
In summary, locking large PDF files not only keeps your documents safe but also enhances your workflow efficiency. With this feature, you solve the problem of data breaches and unauthorized access. You can focus on what matters most: managing your content and collaborating with confidence.
For pdfFiller’s FAQs
Below is a list of the most common customer questions. If you can’t find an answer to your question, please don’t hesitate to reach out to us.
What if I have more questions?
Contact Support
How do I lock certain fields in PDF?
1. With the form fields added to the PDF, right-click on the Signature field you are wanting to edit and choose Properties. Then from the Signed tab, choose to “Mark as read-only” and select the fields you want to lock after signing. Finally, Close.
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