IS THIS CONVERSION NECESSARY?
If you only sell on Amazon and don't give your books away, you may not need to convert your docx at all. You can successfully upload a Word docx document and the converter behind the scenes at Amazon KDP will convert it usually without a problem.
HOWEVER, I would caution you that you should do all of your styling using the style gallery. I have a few videos on my YouTube Channel that will show you how to format and how important using the style gallery is.
That being said, if you use the style gallery, don't give your books away and only sell on Amazon, you are good to go with only a Word document.
EBOOK GIVEAWAYS - THAT'S ANOTHER STORY:
If you, however, are self-publishing and are planning to do your own marketing, giving away your book, especially when you are just breaking in as an author is crucial. Once you decide to give away your books, you will need a PDF document and an ePub document.
As I'm sure you already know, you can create a PDF inside Word, so that's not a problem. However, you will need a conversion program to create the ePub. I use the program called Convertio.co. This is a paid plan, and it comes to $9.00 a month at the time of this blog. If you only have one book, you can sign up for one month and then stop the service -- but check to make sure that's an option before you do that.
Otherwise, you can take a trip over to Fiverr.com and search convert DOCX to ePub and see who comes up. One word of caution: I tried this and Fiverr is now defaulting to a slightly higher price on almost all services, so look for the drop down that lets you put in your budget. I was able to find someone who was willing to do it for $10.00.
However, if Convertio.co allows you to quit after one month, you may be able to use it a few times. I offer this suggestion because I remember when I was brand new, I had to do things multiple times -- I'm not even sure why. So be aware that you may want to do more than one per month.
Another example is that I am presently preparing an ARC copy of the document and will need to add several pages for the final manuscript when it's back from the Final Edit. So, I will need two conversions at least on this one book. So be aware of this type of thing.
TO SIGIL OR NOT TO SIGIL:
Sigil is a program for making or polishing up ePubs after conversion. I always had to get rid of a lot of crazy codes in the ePub so that's why I used Sigil throughout the years.
However, what I noticed with this last time I used it, and this is because I have disciplined myself to use only the Style Gallery in Word and not use individual changes, I had very little clean up in Sigil. I could have even skipped the Sigil step all together.
If you are intimidated by computer code -- and it can be a little tricky -- then you may want to clean up your formatting in Word by using only the Style Gallery.
I have a video below where I go into a little detail as to why you have to be so careful with sigil and computer code. I wish I had known about the importance of the style gallery when I first started, but at least I know now and I'm passing on the knowledge to you!
WHERE TO GET THE TOOLS:
Here is a link to go to Convertio.co This is a service you use online. There is no download or anything. You simply upload the Docx file and then download the epub.
Here is a link to go to Sigil to download it. This is an actual free program that will download and put an icon on your desktop. When you want to open it, you will double-click the icon and it will open a blank document. Then you will click on File > Open and bring in your converted epub.
IT HELPS TO SEE IT IN REAL LIFE:
Below is a short video I made going through the process starting from pulling the document into Convertio and then taking it through the rest of the process to checking it on KDP. I hope this helps you if you are struggling in any way or if you are new and just need information.
https://youtu.be/QVi1XSiQSRs