Optional Class Features
Source: Tasha’s Cauldron of Everything p. 24
You gain class features in the “Player’s Handbook” when you reach certain levels in your class. An optional feature is an additional feature that you can gain beyond these.
Unlike the features in the “Player’s Handbook”, you don’t gain an optional feature automatically. Consulting with your DM, you decide whether to gain an optional feature if you meet the level requirement noted in the feature’s description. These features can be selected separately from one another; you can use some, all, or none of them.
If you take an optional feature that replaces another feature, you gain no benefit from the replaced one and don’t qualify for anything in the game that requires it.