Editable text box for users to add comments in report

Hi Anonymous 

This can be done by using a Powerapp. You can build a powerapp to collect user comments and also log date and time and Report etc. then save this data into a Sharepoint list etc. This can then be integrated with the Power BI report.

You can find out more here : Power Apps visual for Power BI - Power Apps | Microsoft Docs

However, there are many problems with this, note the long list of limitations in the documentation, the restricted browser support, and the different licencing requirement (PowerApps are licenced separatly from Power BI).

But mainly this is replicating the Comment function already in Power BI. If you've not seen it the comment function logs user, date Time and comment, other users can be tagged, and an optional bookmark can be saved to highlight the point made. 

To my mind this is much to be preferred to handcrafting your own solution.

see: Add comments to dashboards and reports - Power BI | Microsoft Docs

hope this helps

Stuart