EPPlus VS DocX

Like others, I recommend using the ImportExcel module. It uses and wraps EPPlus Software (EPPlus - Create advanced Excel spreadsheets using .NET (GitHub Project Old / New)) which is a DLL that is included with the ImportExcel PowerShell Module.

There is some additional samples at their old (abandoned) branch: https://github.com/JanKallman/EPPlus/tree/master/SampleApp

Love this version: https://www.nuget.org/packages/EPPlus/4.5.3.3

EPPlus ExcelDataReader NPOI

For reading JSON -> e.g. ServiceStack.Text. For writing into Excel -> Use EPPlus library version 4.5.3.3. This is the last version of EPPlus under the LGPL License (aka free for commercial uses). You can install it using Nuget Package manager: Which library were you using for CSharp?

If you mean library, the older version of EPPlus is still available.

My suggestion would be to avoid using Office Interop. When you use it, it creates a dependency on Office, meaning it has to be installed on the machine in order for your app to run. That's completely unnecessary and wasteful from licensing perspective. There are several packages on Nuget that allow you to work with Excel sheets without the need for Office to be loaded. A couple would be ClosedXML and EPPlus.

DocX (by XCeed, open source, non commercial use)

If you still want to give it a go yourself, I'd suggest you take a look at the many code samples/API's available in VBA or C#, those could be translated to or used in PoSh. Examples: DocX Aspose.Words GemBox.Document UseOffice.Net

No I mean https://github.com/xceedsoftware/DocX - I've owned it a few years back, but they changed license now where commercial usage is very restrictive if at all possible, but also it's limited to .NET Framework only.

Try https://github.com/xceedsoftware/DocX instead of interops.

I high recommend don't use microsoft interops. There is great word library DocX.

Check out the DocX package: https://www.nuget.org/packages/DocX/