There is a new Feature Requests category on this forum to suggest, discuss, and vote for new features in ParaView. To vote for new features, please click on the heart-shaped “like” button in the initial post with the request in the topic, as highlighted below:
The ParaView community previously had a ParaView UserVoice page to add and vote on feature requests. That page has no been locked, but it will be kept around as an archive of past request. Suggestions on that site that had more than 10 votes have been copied as new topics in the Feature Requests category. Existing vote totals could not be transformed into likes, unfortunately.