Even after adding a table to your drawing, you can continue to modify it using the commands on the Table tab. For example, you can insert or delete rows and columns.
You can insert rows and columns into your table by selecting a cell, then choosing Insert Left, Insert Right, Insert Above, or Insert Below, as desired.
Similarly, delete rows and columns from a table by clicking into a cell, then selecting Delete. Choose your desired deletion option from the drop down menu.