Refer to the manual of configure

The configure script is a script that will configure the software that it was distributed with for compilation (if applicable) and installation.

These scripts are often (as in this case) created by GNU autoconf (a tool used by developers specifically for creating portable configure scripts), which means that it will have at least a minimum of a certain set of options. One of these options is --help.

$ ./configure --help
`configure' configures this package to adapt to many kinds of systems.

Usage: ./configure [OPTION]... [VAR=VALUE]...

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Defaults for the options are specified in brackets.

Configuration:
  -h, --help              display this help and exit
      --help=short        display options specific to this package
      --help=recursive    display the short help of all the included packages
  -V, --version           display version information and exit
  -q, --quiet, --silent   do not print `checking...' messages
      --cache-file=FILE   cache test results in FILE [disabled]
  -C, --config-cache      alias for `--cache-file=config.cache'
  -n, --no-create         do not create output files
      --srcdir=DIR        find the sources in DIR [configure dir or `..']

(etc.)

There is no manual for configure as it's specific to the software package that it was distributed with, and some of the available options may depend on the software that it configures (so it can't be a system-wide tool with its own manual). In particular, there are often --with-xxx and --without-xxx options to configure projects with or without some library xxx, and likewise --enable-xxx and --disable-xxx options to enable or disable certain features (not in this shtool distribution though, it seems).

There is often (as in this case) both a README and an INSTALL text file distributed with the source code. These files will describe the software and how to configure it and install it. The INSTALL document will often tell you how the authors envisage the installation should happen, and you can refer to the configure --help output for how to customise this to your own needs.

configure is a script, not a command, thus there is no man page.

You can find information in the README file and, if the author was kind, a --help option

See https://www.linuxquestions.org/questions/linux-general-1/configure-command-315662/ or similar for a discussion.