GeezerVison

To edit the contents of an existing table in VisualEditor, simply double-click on a cell. You can then change the text, links and references, just like anywhere else in the article.

To format a cell, just click once to select it. You can then use the Content cell  menu to designate it as a header.

The A  menu also allows you to make cells bold or italic.

Finally, you can merge cells, by selecting a set of cells, then clicking the "Merge" button.