Yes, with Magento 2 Advanced Promotions Extension, admin can apply promotion rules with/without coupon code.

Read this Extension's configuration guide to setup the promotion rules without coupon code.

Here are the few useful resource to help.
1. How to Create Promotions in Magento 2?.
2. Explore Advanced Promotions Extended Functionalities [Upgrade].
3. Drive More Sales with eCommerce Gifting & Promotion Strategy.