In the Preview app in Mac OS Mojave it's easy to be able to split PDFs into a separate document
and also to merge PDFs into one document.
So, let's take a look at a sample PDF that has four pages in it.
If you don't see the left sidebar here, click here and instead of having Hide Sidebar choose
Thumbnails.
Now you can see there's four pages here and you can click on anyone to view the page.
So let's say we want to split this into two separate PDFs.
One with the first two pages and one with the second two pages.
There are a lot of different ways to do this.
For instance, we can simply delete the pages out of this.
So I can grab the third page and hold the Command key and grab the fourth page.
Hit the Delete key and now I have a document with the first two pages.
So that would work in some cases.
Go into Command Z to Undo that.
I could also do the same first thing with the first two pages, Command click each one
of those, and hit Delete and now the third and fourth pages are the two pages there.
So I can basically duplicate the file and do that to each one to get what I want.
A neater way would be to use Copy and Paste.
So I'm going to do Command, select the first two pages and do Command C for Copy or just
Edit Copy.
Then file New From Clipboard or Command N.
This creates a new document that has the first two pages in there.
So I'm going to Save that.
Command S. I'm just going to save it to the desktop as Demo 1 and close it.
Notice I have them opening up in tabs there which is a great feature of Preview to be
able to use multiple tabs.
I'm going to now go and do the same thing with three and four.
Command, click, and now I just have three and four selected.
Go into Copy, New From Clipboard, and you see I get the last two pages there.
Command S to save and save that as Demo 2.
So now I've split it up into two separate documents without altering the original document.
Which is really nice.
You can also do this with Drag and Drop.
So I can Command and select these first two pages here.
Drag them and it creates a document there that has those two.
I can Command, select those and Drag them and now I have two documents here.
Pages 1 and 2.
Pages 3 and 4.
So really easy ways to create PDFs by splitting apart the pages of an existing PDF.
So let's say we want to merge two documents together.
So let's merge these two that we have created.
I'm going to do that by opening the first one and then a simple way to do it is to just
drag and drop the second one here into the left Thumbnails bar here.
Just drag it after it.
You can see I can actually insert it inbetween existing pages.
Now I've got what I want but I'm just saving it as a new version of the first document.
Which may not be what I want because I may want to preserve the first document and the
second document and create a completely new one.
So let me Undo there and I've got the first document just like I had before.
Let me select both of these pages here.
I'm going to Copy and then create a New From Clipboard.
Now here's a bug in Preview.
When you do that you get two versions, two documents, untitled 1 and untitled 2 here
on the left sidebar and that only happens when you select all the pages of the PDF and
do Copy and New From Clipboard.
So to correct this bug I'm going to close the second document here.
This untitled 2.
I'm going to click on the first page of it, go to File, and Close Selected PDF Document.
Not Close Window but this one.
That will just get rid of that unnecessary second copy.
Now I have an untitled document with two pages.
I can drag and drop this in here and now I have a document with all four pages.
I can Save and I'll save this one as Demo copy and it puts it there.
So now I have a merged document with those.
You could also go and duplicate the first document.
So I can select that and do File, this is in the Finder.
File, Duplicate.
Now I've got this copy here and I can open that up and drag this second one into it.
I can also open up the second document, if I want, select the pages there that I want
and drag those from one document to another.
So this gives you more flexibility because now I can actually go and select a few pages
from one, a few pages from the other, and create a new document.
Save that.
So for instance I could open this document here, let me select page 2.
I'll do Copy and New From Clipboard.
There's page 2.
I'll open up the second document and I'll select page 4.
Actually I'll drag from here into the Thumbnails bar here and I've created a document that's
page 2 and page 4 now from that.
So you can use Drag and Drop from the Thumbnails sidebar to basically mix and match pages in
a PDF to create a new document.