Aspose.Words for SharePoint has two main features: document conversion and report generation. It integrates with SharePoint and provides a user interface for these features. You can use these features programmatically as well. But, Aspose.Words for SharePoint does not expose the whole document object module like Aspose.Words for .NET does. For example, the MailMerge feature is available in Aspose.Words for .NET; but you cannot use the MailMerge class via Aspose.Words for SharePoint. Please see the System Requirements of Aspose.Words for SharePoint below:
So, in case you just want to open a document and save it to PDF in SharePoint library and nothing else, then you should choose 'Aspose.Words for SharePoint'. On the other hand, if you want to take advantage of the whole Aspose.Words API then I would recommend you please go for 'Aspose.Words for.NET' API. And of-course, you can integrate Aspose.Words for .NET with SharePoint environment. For this, I would suggest you please go through the following blog post and video tutorial: