Under Income, in the Customers list, every row has a glyph on the far right that looks like three vertical dots. It looks like this brings up a menu of additional actions.
From my experience, those look more like drag handles for manually re-ordering the rows.
Three vertical dots to denote a menu feels more like a mobile convention (specifically an Android convention). On the web, a glyph for denoting a menu of extra actions is more commonly represented by a row of horizontal dots, like an ellipsis (for example, look at Microsoft Teams or Azure DevOps).