In Spreadsheet matrix, text boxes are used for allowing the user to enter text input.
Settings available with Text Input in Spreadsheet Question:
Text Input Rows: You can customize the number of rows that would be available in the text box.
Text Input Width: You can customize the Width of the text box.
Custom Validation: This setting is available with spreadsheet question type specifically. Here you can assign the specific numeric values across each rows or each columns or across the entire question. For making this custom validation work you would need to mark this question as validated.