This simple addon for Atlassian Confluence provides Add Row Button macro to Confluence editor. Drop macro just after any table on page. Note that the last row of the table is now hidden and the macro has turned into “Add Row” button.
Click the button to insert a copy of the hidden row with all its contents and formatting. You can make as many copies of the row as needed thus turning it into a template row for the table. This can be used with Confluence ‘instructional text’ – placeholders for user input.
Removing the button from the page will unhide the hidden row, of course.