Can work wifi see what I’m doing on iPhone apps (Instagram, Facebook/Messenger, Reddit)?

I have to log in to my work wifi. I was wondering if they can see what I’m browsing on my phone. If I’m scrolling through Reddit app, can they see each image/link that I pass through? Is the app using HTTPS?

Can they see the images that I click on through the Instagram app as well as my messages on Facebook messenger?

Privacy Galaxy!