How does one stretch or narrow the width of a column?
I was initially confused that adding space characters to the end of the line did not increase the width of the column as others have said. It turns out that you have to add more space characters than you may assume in order for the column to grow.
Here is some experimentation with a table cell that I want to be displayed using a single line of text. By adding 20 space characters to the end of the text, the cell/column begins to grow. But it takes 47 space characters to eventually make the cell/column wide enough to fit the cell's text in a single line.
I’d kite to add to Matt P & others answers. Their descriptions are perfect until Apple improves it. As a refinement, use your top row for column headers to add the spaces in for extra width. (I like to underline & bold this row so I don’t accidentally delete it.) Start with first column header and add spaces at end until column width bumps wider. Keep going if you want it wider. Then go to the next column you want to widen & repeat. Column width starts out as narrow as it gets. Want narrower columns? Then start out with more columns & experiment. I started with 6 columns when I only needed three. I widened the first and third column and left the 2nd, 5th & 6Th alone and they kept their narrower width. I later deleted the 5th and 6th columns and column 2 bumped wider. Not what I wanted. You may have to live with extra columns that you don’t use. Caution: longer data entries in rows below will widen the whole column. I know, this whole workaround is a pain and I wish Apple should fix it.