A file with an .ai extension is an Adobe Illustrator Artwork file that contains vector graphics on a single page. It uses points to create paths for displaying the image data, thus making it safe from losing image quality if it is enlarged. AI format finds its major usage for logos and print media. AI files can be opened with Adobe Illustrator, Adobe Acrobat DC, PaintShop Pro, and CorelDraw Graphics tools.
Files with DOTX extension are template files created by Microsoft Word to have pre-formatted settings for a generation of further DOCX files. A template file is created in order to have specific user settings that should be applied to subsequent files created from this template. These settings include page margins, borders, headers, footers, and other page settings. Such templates are used in official documents such as company letterheads and standardized forms.
You can also convert AI into many other file formats. Please see the complete list below.