Last updated on
Sep 22, 2025
Lock PDF and Merge PDF for Mobile For Free
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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.
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What our customers say about pdfFiller
See for yourself by reading reviews on the most popular resources:
To Whom It May Concern:
I love your service. I am trying to find work at with a university, and because of your service I am able to apply to campuses without fully online applications quickly by editing my initial application, rather than having to rewrite it every single time.
Thanks a million!
Yours,
Peppe
2014-07-26
Found the "filler" just in time, as I had mussed up the forms sent to me. From then on I just used the forms from the site Had never used it before. Needed government forms, and they were there by form number. Saved me from performing scanning and downloading, then uploading. Neat job.
2015-11-05
First time user who is definitely enjoying the ease of completing PDF documents without the troublesome steps to convert to a word or similar document for editing.
2016-09-06
This is the only app I can erase and…
This is the only app I can erase and fill-in easily so I love it. However, the signing function is glitchy so I use Docu or Adobe sign for that. Still, soooo worth it b/c of the Erase and Fill features.
2019-11-27
it's easy to fill out and send wherever you need to send any important documents
it was simple, and easy to send my documents to wherever they needed to be sent. Also the signature was perfect, I didn't need to print and sign anything, it was all here for me.
2022-12-23
It has been a positive experience, no issues, everything ran smooth from start to finish. I would like to learn more about PDFfiller. I am looking forward to attending a webinar
2021-12-06
Exceptional customer service
Kara was of great assistance working through my billing question today. She was quick to respond and went out of her way to explore all avenues before I realized that the expense about which I was inquiring was charged by another company, not pdfFiller. She was extremely polite and patient.
2021-03-25
its a great web base portal and makes…
its a great web base portal and makes it easy . way better than Adobe for regular day to day document and signature
2025-04-07
Perfect for editing pieces for work
Perfect for editing pieces for work. Efficient, effective & has everything necessary to edit words, pictures, etc.
2025-02-16
Lock PDF and Merge PDF for Mobile
Protect your documents and combine files easily with the Lock PDF and Merge PDF feature for mobile. This tool offers a simple solution for managing your PDF files securely and efficiently.
Key Features
Password protection for your PDF documents
Merge multiple PDF files into one seamless document
User-friendly interface for quick access
High compatibility with various mobile devices
Automatic backup options for document safety
Potential Use Cases and Benefits
Secure sensitive information for work or personal use
Combine multiple reports or documents for easy sharing
Protect important contracts or agreements
Organize travel itineraries or plans in one PDF
Facilitate collaboration by merging contributions from multiple users
This feature addresses your need for document security and organization. By locking your PDFs, you eliminate the risk of unauthorized access. Merging files provides convenience, keeping your important papers in one place. Save time and effort with Lock PDF and Merge PDF for mobile.
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 password protect a PDF on my phone?
Start by downloading the app from Google Play. Next, open it > password protection > import the PDF from your device memory. If you don't see any directory, clear the app data and try again. Now, you'll see two password option owner password and user passwords.
How do I merge PDF files that are locked?
File→Create for creating a new PDF file.
Choose Combine Files Into a Single PDF option.
Click on Add File, add all the PDF files you want to merge.
Add password of the locked PDF files.
Click on Combine.
File→Saves to save the PDF file.
How do I combine secured PDFs without password?
Click File > Print to open the print dialog. Click the PDF menu button at the bottom of the print dialog and select Save as PDF. Enter a file name and location for your new PDF file when prompted. The new PDF file will have the same contents as the original, but no password.
How do you combine PDF files on iPhone?
Run the PDF editor app on iPhone. Tap on the Edit icon in the top right corner of the PDF editor app on iPhone, then select the PDF files you want to combine, finally tap the Merge button at the screen bottom to merge the selected PDF files together into one PDF file on your iOS device.
How do I lock a PDF from copying?
Open your PDF.
Go to Protect Tab.
Click Password.
Enter Password.
Select the Printing allowed dropdown.
Select None means to prevent printing.
Select the Changes Allowed dropdown.
Select None -means the highest level of protection.
How do you combine PDF files on Android?
Select a file in the PDF Viewer file browser by long pressing on the cover image of the PDF. This will start the multi-file selection mode.
Select additional files for merging by tapping them.
Once you're done selecting files, press the merge icon in the multi-file selection bar at the bottom.
How do I combine PDF files on my phone?
Select a file in the PDF Viewer file browser by long pressing on the cover image of the PDF. This will start the multi-file selection mode.
Select additional files for merging by tapping them.
Once you're done selecting files, press the merge icon in the multi-file selection bar at the bottom.
How to Lock PDF and Merge PDF for Mobile - video instructions
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