Guest Entries allows your users to create, update & delete entries from the front-end of your site. Essentially Workshop from the v2 days.
User contributed content
Let your users create and update your site's content, straight from the front-end.
Allow your users to upload images or documents to your entries - on upload, they'll be saved as assets.
Simple spam prevention
Guest Entries provides an optional honeypot you can add to your 'guest entry forms' to reduce spam.
Review the documentation on the Statamic Marketplace.