How to synchronize the fields of Multisite profiles?

Question

WordPress

Good afternoon. In a multisite, on different sites of the network, the user has a different number of fields, how to synchronize them? What would they correspond to the main site of the network? For example, on my main site in the user profile there is a "Skype" field, but on the second site it is not. It is necessary that it be there too and that Skype, which the user specifies on the first site, be synchronized with the second (well, synchronization, as I understand it, is present in the multisite by default).
At the same time, if I want to add a new custom field, so that when added on the main site, it would be added to all sites in the network, and I didn’t have to add it manually to each site.
In general, as I understand it, if the field is on the main site, then it and its value are in the database, but other sites simply don’t use it, since you need to add an output / input form under it, but I don’t understand how to do it automatically .