There is actually a history in the database for structures and templates, but there is no frontend for it. You could check the DDM* tables and you will find it there.
We do it differently. A few years ago, we used Webdav to sync the the structures/templates to the filesystem and put them into git.
https://devcon.dccs.at/ideas-for-template-export
Our next iteration was an extra rest api that allowed us to pull/push structures/templates.
Our current code does it differently again. Structures and templates are created manually, since creation and changes to structures are rare. But templates are in git and deployed. But the templates just contain a single line:
<#include "dccs-templates-bundle_SERVLET_CONTEXT_/global/application_display_template/templates/NewUsersTable.ftl" />
They load the template from our module with the include statement. It basically just needs the bundle name + _SERVLET_CONTEXT_ + the file path in the bundle to load it.
For fragments Liferay does better. I wished, the same feature, to simply implement a fragment processor, was available for templates too.

Thanks Chris, I did not clear about your answer, could you please elaborate the details, I want versioning to Structures , Presentation templates and Widget Template, please let me know how can do that in Liferay DXP same as web content items.

HI Chris, can you please let me how do i create/edit the templates through Liferay Dev Studio/Eclipse and deploy theme through DevOps process and test those templates  and also want to create/edit them in the Liferay frontend and then do version . finally let me know how to connect to webDAV