How can I view certain files from WhatsApp for deletion to free up space?

If I want to view only the sent items on WhatsApp, how can I do that? On Android, how we can go through the File Manager to see them easily. For example, if I only want to delete the sent items — is that possible on iPhone ? causes WhatsApp to block a lot of space... If there are any options for this, please let me know.

[Re-Titled by Moderator]

Original Title: Whatsapp blocking lot of space.