PDF Merge Tool (Windows)
Do you use a Windows PC? Then I highly recommend you to try PDF Merge Tool. This is a small free - and open source - app that does one thing, merge PDF files, and does it well.
To download it on your PC, connect to the SourceForge page that hosts it and click on the green button Download located at the top right. Then open the zip archive you just downloaded, extract the contents to any folder and start the program PDF Merge Tool.exe (which does not require installations to work).
At this point, explaining how the program works is almost superfluous. All you have to do is drag and drop the PDFs to be merged into the main window of PDF Merge Tool, arrange them in the order you prefer (using the buttons Move up e move down) and pigiare sul bottone Go! to generate the final document.
Note: PDF Merge Tool requires Microsoft's .Net Framework 3.5 to work. If you are asked to install it when starting the program, accept by clicking on the button Download and install this feature.
Preview (Mac OS X)
On Mac you can merge multiple PDFs without using third party applications. All that is needed is Preview, the default software of OS X for viewing images and, in fact, files in PDF format. The procedure to follow is very simple.
After opening the first PDF with a double click, you need to select the option Miniature from the menu Vista Preview and drag all the PDFs to be merged into the sidebar of the program.
Then you have to use the mouse to arrange the documents in the order you prefer, select the option Print from the menu Fillet and choose the item Save as PDF from the drop-down menu located at the bottom left.
PDF Shuffler (Linux)
Linux also has a wide range of free software for editing and converting PDF files. Among these I point out the excellent PDF Shuffler that allows you to merge, divide, rotate and reorder PDFs through a very intuitive interface.
If you are using Ubuntu, you can find it directly in the Software Center of your distro and install it with a simple click on the button Install. Its operation, as just mentioned, is really very simple.
All you have to do is click on the button + located at the top left, select the PDFs to merge and reorder their pages using the mouse. When the operation is completed, click on thehard drive, choose the folder in which to save the unified document and that's it.
Do you prefer to turn to online solutions? No problem. To solve your problems there is SmallPDF, a great free web service that allows you to edit and convert PDFs in various ways.
It works with all popular browsers (Chrome, Firefox, Internet Explorer, Edge etc.), does not require registration and does not have stringent upload limits. It also protects users' privacy by automatically deleting, within a few hours, all documents that are uploaded to its servers.
To take advantage of its function to merge PDFs, link to the page I just linked to and drag all the documents you want to group into the browser window. Then use the mouse to sort the files as you like and click on first Join PDF and then Download the file to download the final document to your PC.
If you want, by selecting the tab Page mode of SmallPDF, you can also move individual pages of the documents you have selected and change their order without changing the rest of the PDFs.
CloudConvert is another great free web service that allows you to convert and merge multiple PDFs with extreme ease. It is a universal converter, so it is not designed specifically for PDF files, but it works great.
It is compatible with all popular browsers, does not require mandatory registrations (although with registration you can increase the upload limit of the service from 100MB to 1GB) and respects the privacy of users by deleting all the files that are uploaded within a few hours on its servers.
To find out how to use it, connect to the site using the link I just provided. Then drag the PDFs to be merged into the browser window, reorder them with the mouse according to your needs and click on the button Start conversion.
Once the conversion is complete, click on the green button Download that appears below and the final PDF will be automatically downloaded to your PC.How to merge multiple PDFs