My pc runs on windows 10, the version of Writer is 6.4
To add a new row, either put the cursor at the end of the last paragraph in the last cell and press Tab or put the cursor anywhere in the last rox and Table>Insert>Rows Before/After.
If your question is about to add a new paragraph below the table, put the cursor at the beginning of the paragraph after the table and press Enter to create a new paragraph.
Sometimes there is no paragraph after the table (you encounter this situation if you inserted two tables without text in-between or inserted a frame [picture, graphics, formula, …] without text in-between), in this case, put the cursor in the last position of the last cell and press Alt+Enter.
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