I am a champion who is wielding a tower shield. I raise my shield, and then Take Cover. On their turns, can my allies attempt to take cover behind my tower shield also?
The Take Cover action requires:
You are benefiting from cover, are near a feature that allows you to take cover, or are prone.
It isn't clear to me if an ally standing behind my tower shield is benefiting from cover, or if my shield is a "feature that allows you to take cover".
The section on Shields (CRB 277) specifically mentions this:
When you have a tower shield raised, you can use the Take Cover action (page 471) to increase the circumstance bonus to AC to +4. This lasts until the shield is no longer raised. If you would normally provide lesser cover against an attack, having your tower shield raised provides standard cover against it (and other creatures can Take Cover as normal using the cover from your shield).
(Emphasis mine)
Here's a portion from the section on Cover (CRB 477):
Usually, the GM can quickly decide whether your target has cover. If you’re uncertain or need to be more precise, draw a line from the center of your space to the center of the target’s space. If that line passes through any terrain or object that would block the effect, the target has standard cover (or greater cover if the obstruction is extreme or the target has Taken Cover). If the line passes through a creature instead, the target has lesser cover.
(Emphasis mine)
This means that you are providing lesser cover to your friend by standing in front of them. On your turn, you Raise a Shield to gain the normal shield AC bonus. The first quoted section on shields states that having your tower shield raised increases the lesser cover that your friend is receiving from your positioning to standard cover (raising the +1 circumstance AC bonus to +2). In addition, your friend can now Take Cover behind you as long as your shield is raised.
