[Theme: Weaver II] Three columns?

Yes, you can specify the width of the theme.

Yes, there is a template for pages which is called Two Column, but the documentation says that if you use two column markers then you get three columns. There also are sidebars available, but you did not mention the word sidebar so I’m only referring to the content area.

Read this FAQ on Weaver’s support site for 3 columns
https://weavertheme.com/two-and-three-column-pages/

The site width is set in Main Options > layout

More support at Weaver’s forum
https://forum.weavertheme.com/