Wallet application

What is NFC?

Why is it impossible to write cards of the "Troika" type or checkpoints (to the university, to the place of work) on the phone, if it supports NFC?

Why is it impossible to write cards of the "Troika" type or checkpoints (to the university, to the place of work) on the phone, if it supports NFC?

Is it safe to store card data on your phone, use Apple Pay, what is the likelihood that the data could be stolen?