Hi there,
I feel like I have tried everything to add a command to a sign. /css give pig 1 is the command I want to add to the sign. I'm not sure how. Is this plugin PlaceholderIAPI supported?

Signshop existed before PlaceholderAPI so it was never designed to work with it. But Signshop has its own placeholders to use within itself. There is a SSQuickrefrence.pdf in the Signshop folder that lists the placeholders as well as some other useful information.

But your sign will likely look like this:

[Command]
css give
!player pig 1

If the command wont fit on the sign you may have to create a custom sign in the signs list of the config that has the full command listed in the commands section of the config. You could then also pull text from the sign with placeholders in the command. For example css give !player !line2 !line3