How to transfer data from PHP server to devices?

Question

PHP

The point is that I want to transfer data from one phone to (let's say) 2 others.

Answer 1

It really depends on what you want to convey. In php, you can make a server where all three phones send an Http request, and one of them makes a request that puts some data in the database, and the other two read it.
If you want the server to initiate data transfer to other phones, then you need a socket connection. Of course, this can be done in php, but php has no advantages over other languages ​​in this area. There is even a stereotype that sockets in php are worse than in other languages.
In any case, you first need to determine what data you want to transfer and how this transfer will be conceptually carried out.

Answer 2

It’s a little unclear what you need ...
Make a simple REST API on the server - on clients, you can send data to the server and you can receive them.