where to get "use-package"? [was: Re: use pdf-tools in Emacs]

[address@hidden]

On 4/27/23 2:30 PM, Tassilo Horn wrote:
> (use-package pdf-tools
>    :ensure t
>    :init
>    (pdf-tools-install))

Executing the above yields error:

Debugger entered--Lisp error: (void-function use-package)
  (use-package pdf-tools :ensure t :init (pdf-tools-install))
  elisp--eval-last-sexp(nil)
  eval-last-sexp(nil)
  funcall-interactively(eval-last-sexp nil)
  command-execute(eval-last-sexp)

Then "C-h f use-package RET" shows it absent.  So installed 
"emacs-devel" but that didn't provide "use-package".  So what needs to 
be installed to acquire "use-package"?

Thanks much.