What are POD types in C++ and why are they needed?

Hello everyone! I started learning C++ and came across the term "POD type". I read the documentation but didn't fully understand it. I've encountered phrases like "trivially copyable", "standard layout" — my head is spinning.\n\nFor example, I have two structures:\n\n```cpp\nstruct Point {\n int x;\n int y;\n};\n\nstruct Person {\n std::string name;\n int age;\n};\n```\n\nI've heard that `Point` is a POD type, but `Person` is not. But why? Both structures contain only data.\n\nI'm also interested in the practical side. Where can this knowledge be useful? I've heard that POD types can be safely copied via `memcpy` and used in union. But how does this work and when is it really needed?\n\nPlease explain in simple terms: what are PODs in modern C++ (C++11 and later), how are they different