Write a project first as a monolith, then transfer to microservices? Or just write microservices?

Question

Software design

The client demands to make a large project in php for him, the project itself wants php, but so that later it would be possible to scale the project and improve its fault tolerance.
He says:
you need to make an authorization and registration system, you need to encrypt the data of his clients, you need the second, fifth and tenth.

Being working in a monolithic style of projects, I do not understand how the microservice architecture is built.

Looking at the examples of microservices, I realized that anyway we all write in the microservice version, or am I mistaken somewhere?

How then do microservices communicate with each other? Only with the help of the API? With JSON?

Suppose a person sent data, the data encryption microservice encrypted it, then the second microservice sends it to the database for saving, the third microservice sends it to the user, and along the way the fourth microservice decrypts the data and the client receives a secure end-to-end picture, document, etc.

Is that how it works?

Answer 1

Premature division into microservices is evil.
Microservices can communicate in different ways - this is json, grpc and mq.
There is no need to move encryption to a separate microservice - this makes encryption meaningless. Use HTTPS in such cases.