By default, any logged-in user with access to Structure can create new structures of their own. However, you can restrict this ability to one or more user groups.

To select who can create new structures:

1. Navigate to Administration | Structure | Configuration.
2. Click Select Who Can Create Structures.
3. Select whether new structures can be created by Anyone with access to Structure or by Users in selected groups/roles.
4. In the latter case, change the selected groups/roles list by selecting second radio button and use Add Group/Role section to add one or more required user groups or project roles. To set up required property, use drop-down selectors to choose either Group or Project option, then choose required group name or project/role combination and press Add button to add it to the list. If project is set to "Any", this means that user should be in specified role for any of structure-enabled projects.
5. You can remove permission option by clicking trash can icon on the right of the option. 
6. Click Apply when done or Cancel to dismiss your changes.