Wrap text fields with custom HTML
There are a number of ways you can handle this. The three best that come to mind are:


Use a theme hook template file to modify the output. You can do this at either the field level or the content type level.
Use Display Suite to create a field template.
Create a custom field formatter with Custom Formatters module. This plays nicely with display suite.


In your case Display Suite is probably overkill unless you wanted to use it for managing all your output. It’s an extremely powerful module that if implemented correctly allows you to not have to manipulate template files.

In either case I would suggest taking a good look at Display Suite as it really speeds up the theming process.