Select which type of form users will use to upload files:
There might be other choices you can choose. If so, these come from plugins you have installed. The basic Coppermine options are the two listed above. For assistance on any other upload methods, please check your plugins and their documentation.
You are encouraged to use the advanced upload form unless you have problems with it.
Since it is your users who will run into these problems, you may want to allow your users to choose the upload method themselves. See the configuration setting "Allow users to choose the upload method".