You can save a webpage as a PDF on a Windows computer using any installed web browser's Print menu and selecting "Save as PDF" from a dropdown menu.

You have the option to convert Google Docs into PDFs and either save them to your computer or send them as an email attachment.

The files with AI extension represent the vector images created in Adobe Illustrator software. Graphics designers use Adobe Illustrator to create different types of images, like banners, logos, ...