Yes, you can assign both general and approval tasks to external users, but the specific method depends on the platform you're using. Most platforms facilitate this through either email-based assignments that provide a secure link to an external user, or by granting limited access through a guest or portal account. When using this feature, it's crucial to carefully manage security settings to ensure external users only have access to the necessary information and to be mindful of what you include in email notifications. 

Hi ​@mstone, 

Welcome to Box Community, and we’re gladly answer your question in regards to Tasks. 

General tasks and approval tasks cannot be assigned directly to external users unless those external users have been invited as collaborators in the folder.

Hope it helps, and please let us know if you have additional questions.