https://www.terraform.io/downloads.html

curl -L --output /tmp/terraform.zip  \
https://releases.hashicorp.com/terraform/0.12.24/terraform_0.12.24_linux_amd64.zip

sudo unzip -d /usr/bin/ /tmp/terraform.zip 

terraform -version
Terraform v0.12.24

Alternatively:

Install terraform on MacOS :

1) Download ZIP file
wget https://releases.hashicorp.com/terraform/0.11.7/terraform_0.11.7_darwin_amd64.zip
2) unzip this ZIP package
3) copy it to your executable path

Install terraform on Windows:

1) Download ZIP file
wget https://releases.hashicorp.com/terraform/0.11.7/terraform_0.11.7_windows_amd64.zip
2) unzip this ZIP package
3) copy it to your executable path