setup lets encrypt in Ubuntu 16.04 on apache

setup-lets-encrypt-apache.sh

 ### To apply ssl certificate free via lets encrypt in apache ###
 sudo add-apt-repository ppa:certbot/certbot
 sudo apt-get update

 sudo apt-get install python-certbot-apache
 
 sudo certbot --apache -d lifeconnect.app
 
 sudo certbot --apache -d lifeconnect.app -d www.lifeconnect.app
 
 sudo certbot renew --dry-run

and for apache if you are generating csr

by

sudo openssl req -new -newkey rsa:2048 -nodes -keyout *.domain.com.key -out *.domain.com.csr

so on common name: you should write *.domain.com

you generally gets this files from comodo or ssl seller.

AddTrustExternalCARoot.crt
SectigoRSADomainValidationSecureServerCA.crt
STAR_domainname_org.crt
USERTrustRSAAddTrustCA.crt

and for generating ca-bundle file
AddTrustExternalCARoot.crt>>USERTrustRSAAddTrustCA.crt>>SectigoRSADomainValidationSecureServerCA.crt

You can check this link
https://support.comodo.com/index.php?/Knowledgebase/Article/View/1145/1/how-do-i-make-my-own-bundle-file-from-crt-files