Laptop encryption for school

I have a MacBook which is connected to my phone & have to get it encrypted for school. I was wondering if there’s any way to secure my texts and photos so that my school can’t see them? I don’t have anything illegal but I would like my stuff to remain private.

I do have an iCloud account and that’s where my laptop is connected- so I can receive texts on my computer and images sync, etc. Would I need to create a new iCloud and just forget about these features? (the main reason I bought the MacBook is because I like how fluid Apple products are with each other).

I hope my concern and question made sense, please give me you tips and advice! I’m happy to answer any questions.