Shapes tab PDF (iOS)

Shapes selected from the Review tab bring up their own respective tabs, which each provide similar options:

Add Comment – Allows you to attach a comment to the specific shape.
Text – Lets you modify the contents a note, as well as add notes to the other annotation types, accessible from the Text field.
Color – Lets you modify the color of the annotation.
Opacity – Allows you to set transparency for the shape color.
Thickness – Specifies the shape thickness.
Line Endings – (For Line tool) adds arrow and shape effects to the beginning and endpoints of the line.
Delete – Removes the annotation from the PDF.