Hello buddies I am learning how to upload/donwload files from https://docs.mendix.com/studio-how-to/pages-how-to-attach-files#4-adding-a-file-manager. It mentions that create a file entity in domain model, but I didn’t get it from my studio pro, Could anybody tell me how to find this entity type? Thanks. but I didn’t find this entity type from my toolbox
The tutorial you're looking at is for Mendix Studio, you have to check out documentation for Mendix Studio Pro.
What you want to do is open the entity from the domain model and select a generalization. Select the FileDocument entity from the System module.