Thank you for using our services.
For that purpose you can use templates. You can populate your templates with controls through the template editor (see attached images). Then when you create a page and make use a certain template it will have the already populated controls (just as with master pages in regular ASP.NET sites).
Please note however that if you add controls to a content placeholder in a template, you will not be able to edit those controls in the same content placeholder when editing a page. You will only be able to do this in the template editor.
I hope that the above will answer your question. If you have more questions, please feel free to contact us.
the Telerik team