While there are ways that appear to work without sysprep, you’ll have a much better time if you just use sysprep.
I learned this the hard way. Sysprep has gotten faster and a bit easier (in some respects at least).
If you don’t use it, you’ll end up with windows licenses with the same universal identifiers, which breaks volume license activation tools.
You can also end up with driver problems if the image wasn’t created on the same model computer and you don’t use sysprep.
If I were to sum up our steps for creating a win 10 image (but like @george1421 said it’s a bit out of scope and would take days to answer in full detail, also we don’t use MDT, just to provide another method) I would say
Download iso of latest version of most recent windows 10 H2 release (i.e. 20H2, ltsb versions are also a trap unless truly neccessary)
Create an unattend file using windows system image manager (see also https://docs.microsoft.com/en-us/windows-hardware/customize/desktop/wsim/windows-system-image-manager-how-to-topics) I personally took the time a few years ago to ready through all the options available, it’s pretty extensive. But you can also make it pretty basic with setting some simple settings, adding some first logoncommands, and then just make sure you read up on using the ‘reseal’ options to make the sysprep phases go in your desired order. (i.e. I have mine go Audit System - adds (but doesn’t install) network drivers to the driver store -> Audit User - reseals to generalize -> Generalize - removes drivers not added by sysprep and makes the image general for any device -> I have it send to shutdown from here -> I Upload it to fog -> When it deploys it starts the specialize phase -> Then it goes through oobe (which you can make unattended, there are some skip oobe options to be sure it doesn’t show, but you want to be sure all settings that would be set during interactive oobe are set by your unattend.xml created with windows system image manager)
Install the iso on a vm (or whereever you want to capture your image from), at the oobe screen after install hit ctrl+shift+f3 to enter audit mode
DO NOT OPEN THE WINDOWS STORE (if apps are updated in the store, sysprep won’t run, it’s a whole thing)
Add customizations/files you want on all machines (some will be removed by sysprep, figuring it out involves some reading and trial and error) and add the unattend.xml file to “C:\Unattend.xml” and “C:\Windows\System32\Sysprep\Unattend.xml” (I like using both places as a fail safe to be sure its used). I personally use custom powershell modules to automate this whole process, scripting it in some way is a good idea once you get it dialed in. I suggest limiting program installation at this step, I have found its better to use a provisioning method such as snapins and or chocolatey triggered by the firstlogoncommands to add programs, easier to keep them up to date and if something goes wrong with an install it’s not then on every single one of your computers.
Run sysprep (i.e. sysprep.exe /audit /reboot /unattend:"C:\unattend.xml") and capture the image to fog
Deploy the image with fog and watch the magic happen
Part of the oobe phase can involve auto-logging in as the administartor and running the firstlogoncommands, which is where (if you didn’t add it during audit mode) you can make sure the fogservice is there and will get your computer connected to your domain.
This is all a very high level overview and there may be some steps in between beyond creating scripts and other infrastructure. docs.microsoft.com has many helpful guides for the available unattend.xml options and creating images, I thought I had some of the more helpful ones bookmarked/referenced in internal docs but I can’t find them at the moment. I’ll share them if I find them later and remember.
If you take the time to do it right and get it all setup, it becomes very easy to create new images and deploy them.
You could also easily use fogs scheduled tasks to deploy the image nightly on machines. You’ll just need to dial in the firstlogoncommands to work they way you want it to.