Its width of the document page

[Slava]

Hello!
And somehow you can put your width of the docx document page. And do not use
section.PageSetup.PageSize = PageSize.A6;

[Vijay Ramachandran]

Hi Slava,

Thank you for using Syncfusion products.

On analyzing further with the given details, we suspect your requirement is to specify the custom page size for a Word document instead of PageSize.A6. If this is your requirement, then you can achieve this by below highlighted code snippet: 

      //Create Word document instance.
      WordDocument wordDocument = new WordDocument();
      wordDocument.EnsureMinimal();
      //Set custom size (width, height) for the section.
      wordDocument.LastSection.PageSetup.PageSize = new SizeF(600, 800);
      //Add text to the paragraph.
      wordDocument.LastParagraph.AppendText("Word document created by DocIO with custom page size.");
      //Save the Word document.
      wordDocument.Save(@"sample.docx");
      //Close the Word document instance.
      wordDocument.Close(); 

If we misunderstood any of your requirement, then kindly elaborate the actual requirement with detailed description. Thereby we will analyze further on the mentioned case and will provided you appropriate solution

Regards,
Vijay R