mkdir certbot
cd certbot
chmod a+x certbot-auto
sudo ./certbot-auto certonly --server https://acme-v02.api.letsencrypt.org/directory --manual --preferred-challenges dns -d *.domainname.com
For putting TXT record in NameCheap:
In HostName, put _acme-challenge, in value put the string given on the command line.
To check whether the txt record is deployed:
dig -t txt _acme-challenge.domainname.com
Then in httpd.conf:
<VirtualHost *:443>
DocumentRoot "/var/www/html/somepath"
ServerName other.domainname.com
ServerAlias *. domainname .com
SSLCertificateFile /etc/letsencrypt/live/ domainname .com-0001/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/ domainname .com-0001/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/ domainname .com-0001/fullchain.pem
ErrorLog logs/ domainname -error_log
CustomLog logs/ domainname -access_log common
<Directory "/var/www/html/somepath">
Options Indexes FollowSymLinks
AllowOverride All
Order allow,deny
Allow from all
</Directory>
</VirtualHost>