You are left high and dry with an initial install of Drupal 7 in terms of text editing.
You can add text and code to content text fields but there is no default GUI text editor which you do get with other CMS'es such as WordPress and Joomla. If the Drupal site is to be passed over to a client for content managing who has no experience with HTML or CSS then this is an absolute necessity. Possibly Drupal 8 will arrive with a default text editor as part of the core product.
The initial install and configuration of the text editor can be a bit confusing and initmidating to a novice Drupal user but once your up and running that pain wil be history.
There are a many text editors out there, this guide will use TinyMCE and CKEditor, TinyMCE is the bundled editor in WordPress and Joomla and CKEditor is also a very popular choice, you can install both in Drupal - plus many more.
The installation process requires a Drupal module and also the editors downloaded from their development home sites.
The key Drupal module you'll need is:
Install this module into your site and enable it.

Now download the text editors, download the latest stable releases:
Unzip these and upload them to:
/public_html/yourdrupalsite/sites/all/libraries/
Once they are uploaded you then can configure the Wysiwig Module - you can do this from the modules page as above or:

