You can buy TM33 Reflect from the Technical Machine Shop located in the Heahea City Pokémon Center. This same shop also sells another four TMs: TM16, TM17, TM20 and TM70.
Heahea City is located on Akala Island. You will gain access to Heahea once you clear the Melemele Island grand trial.
Obtaining TM33 (Step-by-Step)
In a normal playthrough you will arrive at Heahea City from the southwest.
Step 1: Once you exit the stairs, walk east on Heahea’s main street.
Step 2: Keep walking east until you reach the intersection, just past the sign board. Continue walking east, past the intersection until you see the Pokecenter.
Step 3: After walking past the intersection, you will arrive at the Pokémon Center. Enter the building.
Step 4: In the Pokémon Center, walk to the counter on the right side.
Step 5: Talk to the clerk on the right side of the counter. Select “Buy” from the menu.
Step 6: Select Reflect, the fourth item from top to bottom in the TM Shop’s menu. This TM will cost 10,000 PokéDollars.
Reflect Details + Use
|Reflect Move Details
Reflect is a defensive move. When used in battle, Reflect reduces the damage from physical moves by about ⅓ (1,364/4,096).
Reflect lasts for five turns. However, if the user is holding a Light Clay, Reflect’s duration will be extended to eight turns. Reflect remains active in battle even after the user switches out.
If used with a Psychium Z, Reflect becomes Z-Reflect. While retaining Reflect’s base effect, Z-Reflect also raises the user’s Defense stat by one stage.
Tip: The moves Defog and Brick Break will remove Reflect’s effect. Pokémon with the ability Infiltrator will bypass Reflect’s damage reduction.
In competitive play, Reflect is often used in combination with Light Screen. This strategy is commonly referred to as “Dual Screens”.
In a main story playthrough, Reflect can be useful if you struggle against physical-based Totem Pokémon. But overall, most opponents in the main story are too weak to justify using a move slot on Reflect.