https://support.office.com/en-us/article/Which-file-format-should-I-use-in-Access-2010-4ff76778-92fe-4636-81e8-d7f9b2ab860d

The new file format (.accdb)

Access 2010You should use the new file format whenever possible because it supports new features, such as multivalued fields and attachments.Moreover, if you want to convert your desktop database to a Web database by using Access Services, the desktop database file must be in .accdb format.

Features provided by the .accdb file format

• Web publishing with Access Services    

  If you have a server running Access Services, a component of SharePoint Server, you can publish an .accdb file format to the Web, suibject to certain compatibility restrictions. Some design features and paradigms are different for Web databases than for desktop databases — some desktop databases cannot be published to the Web without first making design changes.

  After you publish a database to the Web, you can still open the .accdb file to make design changes, and can also then synchronize those changes with the published version. People can use the published Web database in a browser, without having Access installed.

• Attachment data type    

  The new Attachment data type lets you easily store all types of documents and binary files in your database without excessive growth in the physical size of the database. Attachments are automatically compressed, when appropriate, to maximize space usage. You can attach a Word document to a record, or save a series of digital pictures. You can even keep multiple attachments attached to a single record.

   

  https://support.office.com/en-us/article/Which-file-format-should-I-use-in-Access-2010-4ff76778-92fe-4636-81e8-d7f9b2ab860