Create a Single PDF File From Multiple Scanned Image Pages
Using any word Processor (Microsoft Word, Libre Office, Open Office, Apple Pages, etc), open a NEW document.
(Optional) Transcribe the letter into a “readable” format, so that others don’t have to try deciphering the letter each time they want to read it. This may require some work on your part.
(Optional) If different individuals are mentioned in the letter, then put some additional information into the letter about that person. It could be a FamilySearch #, birth/death years, who they were related to, and so on. This makes it easier to understand the relationships that are described in the letter.
(Optional) Transcribe the words from the letter into the word processor.
If you have added the above information, then using the “Insert a Page Break” menu option, create a NEW page to place the first image AFTER the transcribed letter page.
Start by adding the first scanned page. You can usually do this by using the word processor’s “Import Function”, OR simply dragging the scanned image file onto an empty page of the word file. Expand the image to take up most of the page and maximize the image readability.
After the first image, insert another page break, and add the 2nd page of the letter. Repeat this process several times until all pages have been added to the document.
Save your file as an editable Word document so that you can go back and edit it if you need to later, AND THEN save the document to a PDF (Portable Document Format) file as well.
FamilySearch will take PDF files up to 15mb. If the file size is large, like more than 14-15 mb, then use the Reduce File Size menu option, which can significantly reduce what size your file is. There are also online PDF compressors that can help with this as well.
This PDF file can then be uploaded to FamilySearch as a single file with all your scanned pages included.