Even about ~5 years back this was a popular notion that particles were being made from waves or light with fields whose excitations manifest as particles. But modern physics has changed the viewpoint, as far as I know, electrons are fundamental particles, so they aren’t made of anything. They’re excitations of the electron field (not to be confused with the electric field).

If had to explain, in an atom the electron field gets the localized shape it has because there are also nearby excitations in the quark field (in the nucleus). The quarks are charged and interact with the electromagnetic field, which also interacts with the electron field.

So you basically have three fields at play here: quark field, electron field and electromagnetic field. They all interact together such that they each get a particular "shape".

What we mean by "interact" is that mathematically the value of one field depends on the value of another field.

In Quantum Mechanics (actually Quantum Field Theory) the "value" of a field is something a bit more abstract than e.g. a single scalar number or vector quantity - instead the "value" is called a "state". I can't really explain what a "state" is in QFT so easily without the Bra-ket, except that it is indeed the mathematical "object" that fully describes what state or configuration the field/particle is in.