I am creating a data table where the last actions has multiple actions needed, I stumble to the concept of using either vertical and horizontal ellipses, but what is mainly the differences in terms of its function?
The horizontal ellipsis was borrowed from typography where it is used to denote that there is more content that isn't shown in the current view. This is often used at the end of news story teaser text to show that there is more to read. It is also sometimes used in the context of a menu or toolbar to show that there are more options available.
The vertical ellipsis (often also referred to as a 'meatballs' or 'kebab' menu) is a combination of the ellipsis and the 'hamburger' menu. This is also used to signify that there are further options but works for designs with limited horizontal space.
The difference is subtle but you really should think about the context your users are seeing these in and if you might, at some point, need to distinguish between the two different actions.
This article sheds more light on how the ellipsis is used and understood: https://medium.com/@jsaito/the-mighty-ellipsis-6c2c00ddc864