You can make general settings for tables via the dialog box of the ribbon command Table | Properties. These always apply to the entire table. For example, this command allows you to change the borders and shading of all table cells at once.
To open this dialog box, position the text cursor in any table cell and then choose the ribbon command Table | Properties 
. (Click directly on the icon itself.)
Alternatively, open the dialog box by clicking on the small arrow of the icon and selecting Table in the menu that appears.
Note: You can also open this dialog box by double-clicking on one of the borders of the table.
The following settings can be made in this dialog box:
Format tab
On this tab, you can change the size and position of the table.
Borders tab
Here, you can change the borders and gridlines (the lines between the cells) for the entire table.
The options on this tab correspond to those described in Changing cell properties ("Borders tab").
Cell shading tab
Here, you can change the shading of all cells in the table.
The options on this tab correspond to those described in Changing cell properties ("Shading tab").
Cell format tab
Here, you can change the format (alignment, margins, etc.) of all cells in the table.
The options on this tab correspond to those described in Changing cell properties ("Format tab").
Table fill tab
Here, you can change the fill of the table as a whole.
The result is basically identical to changing the shading of all cells in the table (for example, using the aforementioned Cell shading tab). The Table fill tab contains the fill options, which can be applied as effects via the Customize button on the Cell shading tab. These options include, for example, gradients or pictures.
The options on this tab correspond to those described in Object properties, Fill tab.
Properties tab
Here, you can change some general settings of the table.
The options on this tab correspond to those described in Object properties, Properties tab.