Apacheのインストール

apt install apache2

certbotのインストール(snap)

snap install --classic certbot
certbot --apache

Enter email address (used for urgent renewal and security notices)
[メールアドレス]

Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf. You must
agree in order to register with the ACME server. Do you agree?
Y

Would you be willing, once your first certificate is successfully issued, to
share your email address with the Electronic Frontier Foundation, a founding
partner of the Let's Encrypt project and the non-profit organization that
develops Certbot? We'd like to send you email about our work encrypting the web,
EFF news, campaigns, and ways to support digital freedom.
N

Please enter the domain name(s) you would like on your certificate (comma and/or
space separated) (Enter 'c' to cancel):
[ドメイン名]