Majority of users prefer to use default online editor box in WordPress dashboard to quickly write blog posts. By default, the size of post editor box is 20 lines. After you have written 20 lines, scroll bar appears and you have to scroll up or down to view content being written. Few users may want to have more screen space or area in the post editor box. You can easily increase or decrease size of Editor box in WordPress dashboard.
Permanently increase Post Editor box size – In WordPress dashboard, click on Settings > Writing options. On the Writing Settings page, you should see “Size of the post box” option. Increase the current value (of 20) to say 40 or 60. Then click Save Changes button at the bottom. From now on, post editor box will have bigger size for easy writing and viewing.
Temporary method to change Post Editor box size – While writing blog post, you can increase or decrease post editor box size quickly using quick drag with the help of mouse. While in visual editor mode, drag post editor box from bottom right part. You can stretch down-right for enlarge post editor box or up-left for smaller sized post editor box.