I love to use multi-page PDF files to publish family history books. (They avoid the common problem of JPEGs and PNGs, where each page is a separate file that need to be found and then read sequentially.) In a multi-page PDF, you can have a fully formatted document or book, complete with photos, charts, etc. in a single file. And unless it has an unusual number of photos, it should weigh in at less than the maximum size of 15 MB allowed by FamilySearch. In my experience, this should accommodate 200 pages or more. And every computer or device can read them, unlike some file formats. (I have probably already told the tale of the CD of family history I received from a cousin in Australia, in a MS Publisher format that it took me 6 months to decode. Lesson learned: publish in a universal file format!)
How to Do It?
In most cases a word processor is the easiest place to create a multi-page PDF file, because it is the most familiar. And they make it easy to include photos, maps, charts and other things of interest. Once you have the book created in Word/OpenOffice/LibreOffice or whatever, use the software's ability to export/print the file as PDF.
What if your wordprocessor doesn't have this feature? If you are using Windows 10, choose Microsoft Print to PDF as the "printer".
If your wordprocessor and your operating system both lack this ability, download and install the free PDF Creator (or similar), and use this as the "printer" to generate PDF versions of word processor files.
I keep the master copy of each book as a word processor file, so it is easily changed.
Note that the multi-function printer/scanner/copier in my small Family History Center also has the ability to scan multiple pages into a single PDF file. It may take a little experimenting to become comfortable with it, but it has the advantage that any printed page can become part of a PDF file. (I believe that each page is handled as a large photo, so the resulting file will be larger than one generated from a word processor.)
I discovered a third cousin who is interested in family history. In fact her husband is a software engineer for FamilySearch.org How cool is that?
As I wanted to share with her some family books I had created, it led me to reexamine them. I discovered that one of them had never been uploaded to FamilySearch Memories, and another had a page that listed the birth and marriage details of my living siblings. Oops! That should not have happened!
So I deleted the existing copy from Memories, and created a new version of the book by deleting that page in my master copy and exporting a new PDF copy. Then I uploaded the new version to Memories and tagged it to the main people in the book. Mission accomplished!