Drafts has two versions, an iOS version, which runs on iPhone, iPad and includes an Apple Watch app, and a Mac version.
The Mac version is recent and not quite as full-featured as the iOS version (which has more powerful automation actions which are not yet shipping in the Mac version), but, yes, they are both part of the Drafts family and sync data across all versions with iCloud.
Both have a free version, and a Pro subscription, which unlocks advanced features. Information about Drafts Pro.
Pro can be purchased on either iOS or Mac, and a single subscription on either platform can be shared through your iCloud account.
Hope this helps!