Why can I not select vertices in edit mode?

Hi all! I’m very new to blender and would love it if someone would be able to help me :slight_smile: Why can I not select vertices in edit mode? I managed one time and now it seems to be that my options have dissapeared? I’ve attached a screenshot. Thank you so much!!

Screenshot 2021-12-11 at 22.59.14|690x373

It looks like the geometry was created with a modifier. You can select the vertices of the original geometry, but not the result. Or apply a modifier.