Extract Data from PDF Tables in C# | https://blog.aspose.com/2021/06/10/extract-table-from-pdf-using-csharp/

extract-text-from-pdf-table-specific-area.cs

// Load source PDF document
Aspose.Pdf.Document pdfDocument = new Aspose.Pdf.Document("sample.pdf"); 

// Select the page and extract its square annotation
var page = pdfDocument.Pages[1];
var squareAnnotation =
	page.Annotations.FirstOrDefault(ann => ann.AnnotationType == Annotations.AnnotationType.Square)
	as Annotations.SquareAnnotation;

// Create table absorber and visit the page
Aspose.Pdf.Text.TableAbsorber absorber = new Aspose.Pdf.Text.TableAbsorber();
absorber.Visit(page);

// Loop through each absorbed table in the list 
foreach (AbsorbedTable table in absorber.TableList)
{
	var isInRegion = (squareAnnotation.Rect.LLX < table.Rectangle.LLX) &&
	(squareAnnotation.Rect.LLY < table.Rectangle.LLY) &&
	(squareAnnotation.Rect.URX > table.Rectangle.URX) &&
	(squareAnnotation.Rect.URY > table.Rectangle.URY);

	if (isInRegion)
	{
		// Loop through each row of the table
		foreach (AbsorbedRow row in table.RowList)
		{
			// Loop through each cell in the row
			foreach (AbsorbedCell cell in row.CellList)
			{
				// Loop through the text fragments and print the text
				foreach (TextFragment fragment in cell.TextFragments)
				{
					var sb = new StringBuilder();
					foreach (TextSegment seg in fragment.Segments)
					{
						sb.Append(seg.Text);
					}
					var text = sb.ToString();
					Console.Write($"{text}|");
				}
			}
			Console.WriteLine();
		}
	}
}

extract-text-from-pdf-table.cs

// Load source PDF document
Aspose.Pdf.Document pdfDocument = new Aspose.Pdf.Document("sample.pdf"); 

// Loop through the pages                      
foreach (var page in pdfDocument.Pages)
{
	// Create a table absorber and visit the page
	Aspose.Pdf.Text.TableAbsorber absorber = new Aspose.Pdf.Text.TableAbsorber();
	absorber.Visit(page);
	
	// Loop through each absorbed table 
	foreach (AbsorbedTable table in absorber.TableList)
	{
		Console.WriteLine("Table");
		
		// Loop through each row in the table
		foreach (AbsorbedRow row in table.RowList)
		{
			// Loop through each cell in the row
			foreach (AbsorbedCell cell in row.CellList)
			{       
				// Loop through the text fragments
				foreach (TextFragment fragment in cell.TextFragments)
				{
					var sb = new StringBuilder();
					foreach (TextSegment seg in fragment.Segments)
						sb.Append(seg.Text);
					Console.Write($"{sb.ToString()}|");
				}                           
			}
			Console.WriteLine();
		}
	}
}

Read the article: https://blog.aspose.com/2021/06/10/extract-table-from-pdf-using-csharp/