That image itself, you can find at Google Material Symbols and Icons.
What you’re asking for is a pop up or modal. To do this in Thunkable is a bit of additional work but definitely doable.
Using the Group or Layout component, you can set its visibility to true when the user clicks on the vertical elipses icon. You’d want to add a close icon in the modal itself so that a user can click on that to “close” the model (i.e. set its visibility back to false).