Using JIRA provided functionality
Data in a table grid can be exported, together with the other issue data in printable (PDF), XML or Word format.
Select the appropriate view in the issue.
The table grid is then formatted such that you can properly export it to the required format.
Using the Midori PDF View add-on
If you really need flexibility configuring the output, have a look at the Midori PDF View add-on.
Check following video provided by the people at Midori, showing some of the capabilities when combining PDF view and Table Grid Editor
Exporting Table Grid to Excel
Unfortunately, Table Grid does not provide out of box solution to export Table Grid data into Excel. We are working on all steams to make it possible, however, due to some technical difficulties, it could take some time. So far, we could not provide any timeframes on this.
Workaround: Connect excel directly to the database where your Table Grid data is stored (using ODBC, for instance)