There are 2 types of Template URLs for different kinds of use:
Template Start URL is a mechanism that initiates specific templates from a remote location. Opening the Start URL triggers the process, allowing it to begin. This functionality can be used in conjunction with Jira Automation rules to activate the process based on the selected trigger or through any other third-party application capable of initiating URLs.
Template View & Edit URL is just a simple URL that is used to open the Template details directly.
Instruction on how to get Template Start URL
Go to Templates, hover over the needed Process, and click on the Link icon.
By default, the Template Start URL is off. Turn it on to get the link. Now, you can copy and use this URL as a trigger for Start Template in such third parties as Jira Automation.
When you activate the Template Start URL, a Link icon will be shown on the process line in the Grid.
Once the URL is triggered, the system will start the Process.