With an Atlassian account we can try and use the Atlassian cloud products like Jira cloud, Confluence etc.
We can signup for free to try the Atlassian Cloud products.
We can use existing Google credentials or an email to signup for the free trail.
For email signup the mandatory things are an email address, strong secure password, First name and last name.
Unlike many other signups, there is no credit card required to try the products.
Jira Software Server
If you are not interested in Cloud products, you can host and use the Jira Software Server. Jira server allows a lost of customization and control over the instance that suits your organization needs. To get started with the Jira software server, you can download from here: