file upload

Not. You do that in the process model.

Unfortunately not possible - see full documentation here: https://docs.appian.com/suite/help/23.3/File_Upload_Component.html#uploaded-files-are-stored-as-temporary-documents-until-submission

"When a file is uploaded, the component updates with a temporary document representing the uploaded file. Between the upload and the submission, the file on the server is an inactive temporary file and not accessible except through fv! variables described in the File Name, File Description, and Validations parameters. This is the only way to access file metadata before the file upload is submitted."

Sounds like you should go to my old long-standing Feature Request and click "like" on it, and add a comment in support to amplify it and float it back to the top of Community for greater visibility.  As far as I know, this is in Appian's "product enhancement backlog swamp" along with tons of other useful quality-of-life tweaks, to my chagrin.

I will let you in on the lesser-known fact, though, that the "get content object details by ID" function from the Content Details plug-in, CAN be fed a Doc ID and WILL return a text string containing the (full, un-parsed) filename, even for "newly uploaded but not yet submitted" documents.  With a bit of work, this is a supported workaround that can help with your use case, though you must do it carefully and anyone who attempts this should first have a thorough understanding of how Expression Rules work in general.

Hi deeptis0004,

Whatever I could understand from your question,  we can use document() function to fetch the extension, type or properties of uploaded document. Thanks

Can you please elaborate what is you requirement!!