Explanation
When you use a remote backend that needs authentication, HashiCorp recommends that you:

You do not need to use different Terraform commands depending on the cloud provider you use. Terraform commands are consistent across different providers, as they operate on the Terraform configuration files and state files, not on the provider APIs directly.

Terraform validate reports configuration consistency errors, such as declaring a resource identifier more than once. This means that the same resource type and name combination is used for multiple resource blocks, which is not allowed in Terraform. For example, resource "aws_instance" "example" {...} cannot be used more than once in the same configuration. Terraform validate does not report errors related to module versions, state differences, or formatting issues, as these are not relevant for checking the configuration syntax and structure. References = [Validate Configuration], [Resource Syntax]

The command that makes your code more human readable is terraform fmt. This command is used to rewrite Terraform configuration files to a canonical format and style, following the Terraform language style conventions and other minor adjustments for readability. The command is optional, opinionated, and has no customization options, but it is recommended to ensure consistency of style across different Terraform codebases. Consistency can help your team understand the code more quickly and easily, making the use of terraform fmt very important. You can run this command on your configuration files before committing them to source control or as part of your CI/CD pipeline. References = : Command: fmt : Using Terraform fmt Command to Format Your Terraform Code

HashiCorp Configuration Language (HCL) does not support user-defined functions. You can only use the built-in functions that are provided by the language. The built-in functions allow you to perform various operations and transformations on values within expressions. The general syntax for function calls is a function name followed by comma-separated arguments in parentheses, such as max(5, 12, 9). You can find the documentation for all of the available built-in functions in the Terraform Registry or the Packer Documentation, depending on which tool you are using.
References = : Functions - Configuration Language | Terraform : Functions - Configuration Language | Packer