This option is available for users with the Administrator role only
To manage saved Templates. Follow the steps:
Go to your Jira Cloud instance
On the top menu: Apps → Manage your Apps → find “Easy Templates for Jira” section on the left side bar ➔ Manage Templates
or type on your keyboard "gg" and call "quick access popup"when you can type "Manage Templates"
When navigated - a list of available templates will be shown
You can Edit, Delete, Sort templates
Check the Enabling template fields. Cloud for better understanding Template Editing abilities on Jira Cloud
Click on template name to enable/disable fields, turn on/off child issues creation or change content of Parent/Child issues
If the Project, which issue was a source for a Template, was removed from the instance then the Template might be broken for editing and hidden from using while new issue creation.
There's slight difference in Template Management between Server and Cloud version.
Go to your Jira Server instance
Jira Software ➔ Projects ➔ "Manage templates"
Add, Edit subtasks