Revision services may refer to editing or proofreading, but for many people, the border between them is rather unclear. It's true, they overlap, but there is a difference, and a right order.
Editing: Once a translation is finished, it must be read again and compared with the source (original) text to make sure that nothing is missing, that the meaning conveyed is the same in both, and that it sounds natural to a native speaker of Spanish.
Proofreading: This is usually a monolingual task when the target (translated) text is read again. If editing has been done thoroughly, proofreading will be limited to spotting typos and overlooked spaces, checking term consistency, etc.
For these tasks, I sometimes collaborate with other professional translators. Having a fresh pair of eyes reading a translation ensures better results.
Still not sure if your Spanish text/translation needs to be edited or proofread? Contact me for an obligation-free quote!