Good afternoon, @Healthyway. 

Thanks for providing that screenshot for us. 

Yes, this is legitimate. If the message is within your QuickBooks Online account, it will always be legitimate. 

This request is just from your client and they may need an action done within there account. Here's a guide that can provide additional information:

Manage and track your work with client requests, projects, and tasks

I hope this helps answer question. Feel free to come back if you have any other concerns. Have a great day!