Am I not able to share LMoP with friends in a campaign?

I'm a Hero Tier sub, and purchased the full $15 package, but I don't see anywhere to toggle sharing.

You need a Master Tier subscription to share content. Hero Tier is for unlimited characters, no ads and saving homebrew.

Or to be specific, at least 1 person in the campaign needs a master tier subscription to enable content sharing. Once content sharing is enabled, everybody's content is shared regardless of who is DM or has a sub.

Where is the share toggle?

Quote from Bambreak >>

Where is the share toggle?

 if you have the master subscription, at the top of the campaign page.