Yes you can. Each property has a Notes page, which allows you to enter any miscellaneous information, notes about the property's condition or links to external websites or videos.
Open one of your properties and click the Notes link from the menu on the left side:
And enter any information you'd like in the provided text box:
Tip: Any links you add here will be hyperlinked (clickable) in the property reports.
Everything you enter under Notes will be saved for later and can also be included in the property reports you export for this property. When exporting reports, be sure to enable the Include Notes toggle under Report Sections: