How to customize this one? Thanks!
This is set based on Section selected in the Doctype.
May be you should check DocType’s Doctype to check. May be share the use-case as what you want to achieve with it.
You can also checkout ‘module_name’.py file in the config folder in erpnext. Which doctype under which label can all be configured from here. If ‘sheerland.py’ does not exist in config folder, then create it and have a look at how other modules have provided their view and you can set up your own labels then.