CanIs it possible to change the directory under .github on actions?

We are creating actions to update the Terraform version.

In the process, I want to change the file that defines the actios in .github/workflow, but the file does not exist in actions.

However, I have confirmed that the file exists by using the ls command, but is it possible to change this file with a script in actions?

The files in .github/workflow/ define the workflows. You should be able to access and modify the files as long as you have the checkout action as the first step of a job. You can then run some shell code to commit and push changes using Git. Should it fail, then it’s probably related to the permission level of the default GITHUB_TOKEN (Authentication in a workflow - GitHub Docs). You may need a personal access token for elevated permissions.