Sharepoint 2013 has something built-in to handle Document / Records Management. I don't know about Online 365 though. In any case, it is a big subject and is worth taking time over to implement in a good way. You can also handle it in different ways (as is the way with Sharepoint, more than one way to skin a cat).
I've set up policies on each individual document library and configured archiving / deletion rules or Task generation if you want the document reviewed prior to possible deletion or updating. I've hooked up all document libraries in a site collection to one Departmental Document/Record Task List.
Though you are meant to be able to implement this on the Site Collection level if your Sharepoint is well deployed (in terms of SP architecture)...
See Section 1.2 in this blog post to see how to deploy at the Site Collection level. You can also determine lifecycle rules based on the Content Type. Also, as I have done, you can set rules based on individual document libraries or even folders. Do bear in mind that settings rules at the Document Library levels can be pretty intensive! Make yourself a file in Excel, list your document libraries, define and plan what is needed - you can verify this with the document owners.
If you're doing everything at the Document Library level, you can have a workflow triggered once your Created Date/Modified Date + x years rules are satisfied - see the picture on 3.9; you can set the Action to Run Workflow.
So, to associate an OOTB disposition workflow with your list do this:
- Ribbon (Doc Library)>Workflow settings>Add a workflow>Disposition Approval>Name your Workflow>Select your Task List (I made a 'Document Disposition Task List' for this purpose)>For 'Start Options' choose 'Allow this workflow to be manually started by an authenticated user with Edit Item permissions.'. Then select OK, you now have a workflow, which when triggered, will add a document review task to a Task List.
There might be some additional configuration to allow SP to trigger the 'policy action workflow' and actually run the workflow.
You will need to activate a feature at the site collection level (Site Settings>Site Collection Features>Activate Library and Folder Based Retention. (This only applies if you want to set rules at the Document Library level).
There might be an additional feature that needs activating, I'm not certain though.