Editing: It is checking any type of content to ensure its fluidity. While in visual, its about the relevance and smooth flow of graphics & audio, in text, it deals more with making the literature part of a language seamless.
TSS Content Editing Checks
Proofreading: It is checking the proof of any type of content to eliminate any errors in it, before finalization. In text, it deals more with the grammar part of a language.
TSS Content Proofreading Checks