Add a new table using the insert menu and use your curser to easily adjust column width. Adjust the width to exactly what you want using the horizontal ruler at the top of the document.
Additional table tools are available when you right click (Mac: control & click, Chromebook: alt & click) in a cell.
Included in the Table Properties menu are line and cell colors, set column widths and row height, vertical alignment , cell padding, table alignment and left indent.