Hi!
Redacción means “essay” . It can also mean essay writing manner (you´ll see an example below).
(by the way, “Essay”, depending on which type of essay it is, can be translated to spanish as redacción or ensayo. Ensayo is used for realy well documented and reliable essays, specially the long ones, like books. Redacción ´s meaning is wider.)
Escritura means “writing” in the sense of a writting manner. It reffers to stuff like writing style, composition, and also to the handwriting and stuff like caligraphic style.
It may also reffer to the physical act of writing. In this sense you usually can replace it for escribir in infinitive, and the meaning will remain the same.
(El) Esrito means “writing” in the sense of a text somebody has written. It may reffer to a document, a composition, an essay, a letter… any kind of text. So it is different from essay: a redacción (essay) is a type of escrito, but any other kind of written text could be an escrito.
Some examples:
Hoy he escrito una redacción sobre los volcanes en clase.
I wrote an essay about volcanoes today in class.
Sus dotes de redacción son impresionantes.
His/Her (essay) writing skills are impressive.
Carl Jung escribió numerosos ensayos sobre psicología.
Carl Jung wrote several essays on psychology.
Sus dotes de escritura son impresionantes.
His writing skills are impressive.
***(In this case, unlike with dotes de redacción, there´s a wider meaning that may reffer to different writing skills other than just essay writing skills).
Creo que la escritura es una actividad muy relajante. = Creo que escribir es una actividad muy relajante.
I think that writing is a very relaxing activity.
He dejado el escrito sobre tu mesa.
I left the writing on your table
English is not my mother tongue, so sorry if there´s any mistake…
Well, I hope this helps!