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This is easy to do.
I often provide files as part of my job posts. I do this in a way that is guaranteed to work and which does not violate any Upwork rules.
When I want to provide a file as part of a job post, I put the file in a web directory, not connected with anything else. Then I provide a link to the file in the job post itself. There is no contact information available, but everyone who views the job post is able to download the file if they want to.