Proofreading is the process of examining the final draft of a document or text — after it has been edited — to ensure there are absolutely no errors. A proofreader will review for spelling errors, punctuation errors, typos or incorrect use of regional English (i.e. ensuring that you’re using American English or British English when necessary).
Also known as ‘Structural’ or ‘Substantive’ Editing, Developmental Editing is intended for clients who wish for an editor to work on their manuscript in a more hands-on way. Developmental Editing is less about working on a line-by-line basis, but looking at the bigger picture; giving detailed advice about overall plot (and plotholes), characterisation, point of view and whether or not the themes and elements of the manuscript work well together. It is about ensuring the novel fulfils its potential.