ISO 9001:2015 classifies documented information in two types: documents do maintain and documents to retain. Documents to maintain are, for example, manuals, procedures, work instructions and forms. These documents can become obsoletes, can be change to newer versions, can be updated. When we fill a form it becomes a record and a record, like a photo, documents an event and cannot or should not be changed, cannot become obsolete. Documented information, whatever the type, should be controlled and clause 7.5 describes the requirements. Saying that a document should be retained or maintained is just a way of distinguishing procedures from records, different types of documents.