(Windows) Solution 1: On Adobe Acrobat you are able to crop several / all pages together. Please see: https://helpx.adobe.com/acrobat/using/crop-pdf-pages.html
(Windows) Solution 2: Briss is a free open-source application available for cropping PDF pages at once. It may take a little while getting used to it but once you are comfortable with it, it is pretty fast: https://sourceforge.net/projects/briss/
(Mac) Solution 3: There is a third-party company that offers software for cropping labels. Please download the software form: https://www.peninsula-group.com.