Hi Pankaj,
There are few ways i could think off, you can use either of them:
1.You can control the access by creating a ACL that you can set for write operation on "sn_template" table.
2.By Default, Templates can be created only by Admins or users who have one of the below roles assigned to them. Hence you need not do any customization to the system, just manage the roles appropriately.
For allowing only specific people to create templates, assign them with any of the above roles according to your requirements. Those who do not have these roles, will not be able to create templates.
Also please note template_editor is included in the itil role in the base system, in order that it's not assigned to unnecessary people, please exclude this role from the itil role. Follow below steps to do so:
1. Navigate to User Administration -> Roles, and search for itil.
2. From the Contains Role related list, click Edit.
3. Remove template_editor from the selected list and click Save.
Refer this : https://community.servicenow.com/community?id=community_question&sys_id=84228fe9db98dbc01dcaf3231f96...
Mark my answer correct & Helpful, if Applicable.
Thanks,
Sandeep
