The site administrator can manage the visualization and modification permissions of the pages and the users can perform such operations. In order to set the permissions, when logged in as an Administrator, it is necessary for you to click the Pages button in the drop down menu.
The following screen will appear, which contains the name of the created pages:
Select the name of the page which has to be modified.
Click the button in order to visualize the page settings.
At Permissions, select the individuals who can visualize and modify the new pages. If it is a Child page, this will inherit its security settings of the Parent page which it is connected to.