Artifacts are random drops from chests. These can appear in Regional Caches, Lost Sectors, from Public Events or High-Value Targets. These seem to be rare to very rare drops. Expect to run numerous events before you find one, let alone both.
Each Class has 2 additional subclasses that can be unlocked through gameplay and completing these milestones.
Pages in category "Destiny 2 Artifacts"
The following 8 pages are in this category, out of 8 total.