simple project SRS and documentation for software development?

I work as a web developer and now I have an idea for a project for me and I want to develop it will include (dashboard, website, android & ios app) and I want to make some documents for this project what happens in my company that when client comes with his project the project manager add the tasks ( user stories) on jira with no documents, SRS or any documentation but I want to make simple documentation includes(screens, project cost, user stories, etc..) is there any free simple template for this ?