Which option must be enabled for users to collect files through Smartsheet forms?

Enabling the option to "Upload From Computer" is essential for users to collect files through Smartsheet forms. This feature allows respondents to attach files directly from their devices when filling out a form, making it easier to gather necessary documents or additional data. It streamlines the process of collecting information, ensuring that users can upload relevant files seamlessly along with their responses.

The other options, while related to file collection and integrations, do not provide the direct ability for users to upload files from their devices through forms. Linking from a URL or using third-party services like Google Drive or Egnyte does not allow for direct file uploads within a form structure. Thus, enabling the "Upload From Computer" feature is the specific requirement for file collection in Smartsheet forms.