Apple - Change width of a column in a table in Notes.app on a Mac

The rows and columns of Apple Notes's tables should automatically adjust to fit content. There is no control to explicitly set a width or height, apart from adding whitespace to increase text length (not recommended).

Like @Benj mentioned you can add spaces to one of the cells and the Notes app will adjust the size of the column accordingly. It's not ideal but sometimes it helps when you don't want the text to wrap around