Documentation for JIRA 5.2. Documentation for other versions of JIRA is available too.
The Text gadget displays your specified HTML text on the dashboard.
The Text gadget is disabled by default as it allows users to enter arbitary HTML. To enable the text gadget, please refer to Enabling Plugins section.
The Text gadget should appear as follows on the dashboard:
This gadget is only available if your JIRA administrator has enabled the 'Text' module in the 'JIRA Gadgets Plugin'. It is disabled by default because it is a potential security risk, as it can contain arbitrary HTML which could potentially make your JIRA system vulnerable to XSS attacks.