When it comes to basic designs from another program/software, files in an SVG (2D/vector graphics), DXF (3D), STL (3D), and Gcode format can be imported directly into Easel. You can find out more information about importing external files in these articles:
FAQs - 3D in Easel Pro (3D STL specific files)
In terms of files that may include both CAD and CAM (carving/manufacturing code), as long as your program can export standard g-code, X-Carve (along with its Arduino-based controller) will work with other CAD/CAM software options. Our Easel software has a gcode import option and we have built post processors specifically to support Vectric V-Carve, Aspire, Cut 2D, Meshcam, and Autodesk's Fusion 360. If you want to import gcode files, they will need to be post-processed first to ensure they are in the correct format. We have guides here:
Installing Fusion 360 Post Processor
Importing Gcode from Fusion 360 into Easel
For creating post processors for other programs check our Official G-code Spec for information about how to format g-code so that it can be imported into Easel. If you make a post-processor please contact us so we can add it!