Both
It depends what you are needing to do and the module in question.
As an example we use the AWS security group module from GitHub - terraform-aws-modules/terraform-aws-security-group: Terraform module which creates EC2-VPC security groups on AWS 🇺🇦 whenever we need a SG - both within our own modules and directly in root modules.
We also use the EKS module at GitHub - terraform-aws-modules/terraform-aws-eks: Terraform module to create an Elastic Kubernetes (EKS) cluster and associated resources 🇺🇦 but only wrapped in our own module, which sets various business specific settings (so there is less boilerplate code where it gets used).