using libreoffice api can i open an html document and save as PDF?

I will use solely libreoffice API in C# code, can I open an html document and save as or export as PDF?
Can I also export it as XSLX and CSV?
thank you

What you want to do requires some understanding of so-called filters for the import and the export of documents. Having studied that you can use a sequence like

importDoc = StarDesktop.loadComponentFromURL(theURL, theFrameIdentifier, 0, importArgsArray)
importDoc.storeToURL(theNewURL, exportArgsArray)

If the way LibO presents the imported hypertext document is as you expected, the exported pdf document may also meet your needs.

===Edit1 2019-02-08 15:07 (UTC + 1)===
I found the time to go back to a related task I worked on about 2 years ago.
I reworked it (vers slightly) and added a demo Sub. The code is now contained in a demo.odt also containing explanations. Everything needed to run the demo with an example is wrapped ino this attached zip-archive (original name: I had to append a fake extension (.odt) to be able to upload. Restore the original name after download. Expand the archive into one empty folder and open demo.odt. You need to check the macros for malign code and -after negative result- to permit macros to run the demo.