Searching documents that have annotations, requires a database field be created and noted for these documents. One way to accomplish this is to create a "Tag" field and "Tag" the documents after any annotation has been applied to a document. To recall any annotated document you would then search for this "Tag" field.
Alternatively, a Audit Log Report can be created to show every document that was annotated by any user during a certain time period. To create this report, open the "Tools" pull down menu and select "Audit Log Event Report." Select the user that you wish to run the report for, or select all users if applicable, and the date range you would like the report to be run for. Under Search filters, select "Annotate Document," and then click "View Log." The report will open showing all of the documents tagged by that user, during that time period.