Do you need approval for bringing electricity to a private house from the panel (380V)?

If, however, according to your documents, the 3-phase input and the machine with its terminals are not sealed, then you do not need to coordinate it. By the way, the electrical equipment after the support is considered yours, and you are responsible for it. However, to avoid problems it is better to coordinate this issue with the sales company.

If 220, then you need to coordinate, but most likely you will be sent to a network company, where they will tell you if this line has a reserve for connecting a three-phase consumer, if so, they will give out a technical specification for which you will assemble an input-distribution panel. After that, you will go or call the company that will make the connection (network, I suppose), electricians will come to you, check the correct assembly of the switchboard and perform the technical specifications (for example, the ground electrode and installing the switchboard on a pipe rack, a wall of a house or a support) and connect the cable, after signing all the documents, you will be a three-phase consumer.