Open a shared prototype in mobile browser and use the pinch gesture to open the navigation mode.
A comment icon appears along with number of comments on that prototype. This comment icon appears only when the owner enables commenting option on the prototype.

 next to the comment thread to Resolve, Edit, and Delete your comments. However, you cannot edit or delete comments added by other users.
 next to the comment thread to Resolve, Edit, and Delete your comments. However, you cannot edit or delete comments added by other users. to hide annotations or pins
to hide annotations or pins icon to filter the comments based on reviewer names, time, or status of comments.
icon to filter the comments based on reviewer names, time, or status of comments.  When an artboard is deleted in XD, the web comments for the artboard are no longer available.
 When an artboard is deleted in XD, the web comments for the artboard are no longer available.