Begin with GetUserInput functions in AutoCAD dotNet (c#) Using:

    [CommandMethod("GetPointWCS", CommandFlags.Modal)]
    public void GetPointWCS()
    {
        Document doc = Application.DocumentManager.MdiActiveDocument;
        {
            Editor ed = doc.Editor;

            var pt = ed.GetPointWCS();
            if (EditorExtensions.GetResult == PromptStatus.OK)
            {
                Circle cc = new Circle(pt, Autodesk.AutoCAD.Geometry.Vector3d.ZAxis, 10);
                cc.ToDatabase();
            }
        }
        //Example by www.lisp.vn
    }

    [CommandMethod("Get2Point", CommandFlags.Modal)]
    public void Get2Point_WCS()
    {
        Document doc = Application.DocumentManager.MdiActiveDocument;
        Editor ed;
        if (doc != null)
        {
            ed = doc.Editor;
            Line ln = ed.GetLine();
            if (ln != null)
            {
                ln.ToDatabase();
            }
            return;
        }
        //Example by www.lisp.vn
    }

Source: https://www.lisp.vn/2024/05/lay-toa-do-tu-nguoi-dung-autocad-dotnet.html