How does 'input data' get stored? (Beginner Help)

Simple question/concept I am trying to grasp, thank you in advance for your help, this community has been a huge tool for me. 🙌👏

Okay so... using this example, below (click the link for video), how do I go about storing the 'likes' hypothetically.

https://www.useloom.com/share/e8342acd84e440e283f1ababd758eb0b

Would this be done in a DB? (which would you recommend, I have used MongoDB and have been playing around with google firestore)

How does the data get sent? Is this related to 'state management' in Vue? Is this where tools like nuxt.js and vuex come in handy? (Do these questions even make sense? 🤪😅)

Cheers 🎉

https://www.useloom.com/share/e8342acd84e440e283f1ababd758eb0b