$ wget --version
GNU Wget 1.20.3 built on darwin19.2.0.

-cares +digest -gpgme +https +ipv6 -iri +large-file -metalink -nls
+ntlm +opie -psl +ssl/openssl

Wgetrc:
/Users/xxxxx/.wgetrc (user)
/usr/local/etc/wgetrc (system)
Compile:
    gcc -DHAVE_CONFIG_H -DSYSTEM_WGETRC="/usr/local/etc/wgetrc"
    -DLOCALEDIR="/usr/local/share/locale" -I. -I../lib -I../lib
    -I/usr/local/openssl/include -DNDEBUG
Link:
    gcc -DNDEBUG -L/usr/local/openssl/lib -lssl -lcrypto -ldl -lz
    ftp-opie.o openssl.o http-ntlm.o ../lib/libgnu.a -liconv

Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://www.gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Originally written by Hrvoje Niksic <hniksic@xemacs.org>.
Please send bug reports and questions to <bug-wget@gnu.org>.

$ wget https://www.openssl.org/source/
--2019-12-19 09:20:12--  https://www.openssl.org/source/
Resolving www.openssl.org... 23.41.53.191
Connecting to www.openssl.org|23.41.53.191|:443... connected.
ERROR: cannot verify www.openssl.org's certificate, issued by 'CN=Let\'s Encrypt Authority X3,O=Let\'s Encrypt,C=US':
Unable to locally verify the issuer's authority.
To connect to www.openssl.org insecurely, use `--no-check-certificate'.

wget --ca-certificate=$HOME/Documents/cacert.pem https://www.openssl.org/source/

ca_certificate = $HOME/Documents/cacert.pem

ca_certificate = /Users/your_home_directory_name/Documents/cacert.pem