How to Change the Size of the Custom Fields Box in WordPress

1. Open a Web browser on your computer, and navigate to the location of your WordPress blog's domain. Click the 'Admin' text link at the bottom footer section, and log in with your administrator user name and password.
2. Click 'Appearance' in the left panel. Click the 'Editor' link under 'Appearance' to open the dashboard's customization editor.

3. Click the WordPress file you want to edit that contains the text box. For example, if you want to edit a text box in the header file, click 'header.php' to open the code in the editor.
4. Type the column and row sizes in the text box properties. For example, if you want to create a text box that is 45 columns in width and 35 rows in height, the following properties apply:

5. Click the 'Update File' button at the bottom of the editor. Click the blog link at the top of the editor to open a preview of the text box changes in the Web browser.