Yes, readings can be done by e-mail. I use a person's first name, gender, age and current location to do this. This is my way of linking up. Other psychics may require that you see them in person, speak to them over the phone, or send them some item, like a deck of tarot cards that you have used and put your energy into. That is their way of linking up.
Every psychic is a little different.
Once I feel that I have established a psychic link with you, I will ask my guides to send me an image, a clairvoyant picture that will provide an answer to your question. Sometimes I will hear things, names, dates, keywords, as if someone were speaking very softly into my left ear. If I can't get anything that way, I'll look within myself to see if I intuitively know the answer, or I'll use Tarot cards, Runes or a Pendulum to divine the answer. Just take a pregnancy test. Similarly, if you're feeling sick, don't ask me what's wrong with you.