Drupal does not have a WYSIWYG editor in its core release ( upto 4.7 ). This means users can only post text content on the site and they have to know about HTML tags.

IMO this is a big drawback as not many users would be willing to take this effort. Moreover, visitors will not even be aware of this feature.

Solution – Tip.

1. Easiest way is to use Quick Tags Module. It will add a small toolbar, just like you see on this site above “Post comment” form.
2. BBCode Formatting Bar is another option. Advantage over quicktags is that it has “Image” button also. Disadvantage is that it does not have pictures and quicktags looks better & attractive.
3. TinyMCE WYSIWYG Editor, is loaded with the all the features that you would need. It requires

Tiny MCE drupal module
TinyMCE editor
Advantages

• Complete WYSIWYG editor, with all the features needed.
• Good documentation to get started.

1. FCKEditor is a contributed module and I believe its the best WYSIWYG editor till date. it is fast loading and has good interface.

Disadvantages

• Dependency on third party editor. Updates to Drupal may affect this module
• It slows down the page loads if plugins are used. Generally Font size and font family are plugins. Only if you assume your users to have home broadband connection you can use all buttons.

Input Formats to consider

• URL Filter is a good to add module and it automatically converts web and email address into links. After installing the module. Goto
  administer>>input formats >> Select “Filtered HTML” — configure >> Here check the box “Web and e-mail addresses are automatically converted into links.”
• Insert View and Insert Block are modules to be considered by Site Admins. You have to configure it as mentioned above, and you can put any View or Block on the node.
• Codefilter module is required to allow code in the posts. It is a contributed module and downloaded and setup like URL Filter.