There is no such thing as E, I, S, N, T, F, P, or J in Socionics. It's Ne, Ni, Se, Si, Te, Ti, Fe, and Fi. The "E" and "I" and "p" and "j" are merely indicators of the order of the aforementioned functions. Similarly, in Socionics, people are not extroverted or introverted, functions are.

If your type acronym starts with an "E", it means that your first function is one of the extroverted functions (Ne, Se, Fe, Te). If it starts with an "I", it means your first function is an introverted function. If your type acronym ends with a "p", it means that your first function is either Ne, Ni, Se, or Si. If it ends with a "j", it means that your first function is either Fe, Fi, Te, or Ti. Thank you.