Create a new post or page and add the WP Send shortcode:
[send limit="32" expire="7"]
limit parameter is the file upload limit in megabytes. You also need server support for your chosen value. Most servers come with 32MB by default, but we’ve seen 2MB and 2048MB, so you need to check.
expire parameter which is the file expiration date, in days. A value of 7 is recommended, but it depends on your setup and current offering.
Note that you can have multiple pages with multiple expiration dates. In case you want to create sending plans, you can use multiple filesize limits and multiple expiration days.