Hi @vashon island t thank you for posting in the community! While it is possible to add comments to documents using the iOS version of Lucidchart the notes feature is not currently support in the app. 

However we're always looking for ways to improve Lucidchart and your feedback is the best way for us to do that.  We are continuously looking for how we can make our product more useful and effective for our users and we pass this information directly to our product development team!

Thanks for your request and I apologize for any inconvenience this causes you.