I am pretty new to Trello and am experimenting with copying boards and lists. I want to use a board with predefined lists and cards to which a user can add cards but can not modify list headings or some cards the admin has created. Is there a way of locking parts of the board ?
With Trello, permissions are board specific. At this time, Trello is not able to offer card specific permissions. This is a feature request that has been received, so hopefully this can be implemented in the near future. For the time being, you'll need to have separate boards for privacy.
you can use this chrome extension - https://chrome.google.com/webstore/detail/trello-ticket-locker/dhacecfmakbiagimagjicfcoefkfcbep?hl=en-US but the only downside is all your users needs to install the tool.