Finding a direct, single-click "online" converter for 3D models to FBX is difficult because web-based tools often mistake .xps for Microsoft's document format rather than the 3D model format.

Use the XPS Tools plugin to load the model.

For a true 3D conversion that preserves rigging and textures, use these specialized tools: (Recommended) : The most reliable method. You will need the plugin from The Process : Import the .mesh.ascii file into Blender using the plugin, then go to File > Export > FBX

Converting (XNALara/XPS) files to format is a standard workflow for porting 3D character models into game engines like or professional modeling suites like Autodesk Maya