Essentials users can kick off an Essentials+ trial by checking the Work Items box in Account Settings or adding a Git repository to your Organizations list. The trial lasts for 21 days. At the end of the trial period you can purchase Essentials+ licenses to continue to use these premium features.
Essentials+ Trial vs Essentials+
https://app.intercom.com/a/apps/fwkpa6iz/articles/articles/5742444/show?language=en
Essentials+ Trial Checklist
https://app.intercom.com/a/apps/fwkpa6iz/articles/articles/5743708/show?language=en