The export window can be opened by using File > Export textures.

This window is divided in three sections:

• Export settings
• Output templates
• List of exports

The bottom of the window has several buttons:

• Reset all (only in settings section): reset the export configuration of the project.
• Cancel: close the window without saving any changes.
• Save settings: save the current export settings into the project.
• Export: generated the texture files on disk (and automatically switch to the List of exports section).