The SDKs require a license key and work in demo-mode when no key provided. The entire SDK is available in the demo-mode, but any saving of the PDF files will add demo-watermarks to these files as well as additional demo-labels will appear on rendering of each page. So, please be careful working with documents when the SDK in demo-mode as you may overwrite your files and add demo-watermarks on each page of it! Demo-labels that appear on rendered pages in demo-mode do not modify the document at all.
When you have your license key, you need to set it using IPXV_Control::SetLicKey Method, in case if you are using ActiveX control (PXV_Control ActiveX Control object) or using IPXV_Inst::Init Method when the ActiveX control is not used.
If you are not using the PDF-XChange Editor SDK, but use PDF-XChange Core API SDK, please pass your key to the IPXC_Inst::Init Method call.
Also please note that both SDK's are Royalty based via the purchase of Client Distribution License Packs (CDLP's) and whilst you can fully develop and test all your applications using the Evaluation SDK's prior to purchase to ensure satisfaction, prior to distribution of an application making use of this SDK to any end-user client - the pre-purchase of CDLP's is required.
More information about licensing can be found <there>.
To get your PDF-XChange Editor SDK license key – <click here>. To get your PDF-XChange Core API SDK license key – <click here>.