我建议看一下文档。快速搜索后，我找到了以下访问表单字段的方法：

// For complete examples and data files, please go to https://github.com/aspose-pdf/Aspose.PDF-for-.NET
// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Open document
Document pdfDocument = new Document(dataDir + "GetValuesFromAllFields.pdf");

// Get values from all fields
foreach (Field formField in pdfDocument.Form)
{
    Console.WriteLine("Field Name : {0} ", formField.PartialName);
    Console.WriteLine("Value : {0} ", formField.Value);
}

我找到它的来源：https://docs.aspose.com/pdf/net/extract-form/
这是关于如何填充表单字段的示例：

// For complete examples and data files, please go to https://github.com/aspose-pdf/Aspose.PDF-for-.NET
// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Open document
Document pdfDocument = new Document(dataDir + "FillFormField.pdf");

// Get a field
TextBoxField textBoxField = pdfDocument.Form["textbox1"] as TextBoxField;

// Modify field value
textBoxField.Value = "Value to be filled in the field";
dataDir = dataDir + "FillFormField_out.pdf";
// Save updated document
pdfDocument.Save(dataDir);

来源：https://docs.aspose.com/pdf/net/fill-form/