When do Paladins learn Holy Strike?

Rank 1 at level 6, with later ranks at 12, 20, 28, 36, 44, 52, 60. Visit a class trainer in any capital.

Did Holy Strike change from Classic?

Holy Strike is new in WoW Forever and had no Classic 1.12 equivalent for Paladins.

Rank	Level	Cost / range / cast	Effect	Classic 1.12
Rank 1	6	5 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 25% weapon damage plus an additional 2 to 4 as Holy damage.	new
Rank 2	12	9 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 29% weapon damage plus an additional 4 to 6 as Holy damage.	new
Rank 3	20	12 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 32% weapon damage plus an additional 5 to 8 as Holy damage.	new
Rank 4	28	14 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 36% weapon damage plus an additional 7 to 11 as Holy damage.	new
Rank 5	36	16 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 39% weapon damage plus an additional 12 to 16 as Holy damage.	new
Rank 6	44	17 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 43% weapon damage plus an additional 22 to 29 as Holy damage.	new
Rank 7	52	19 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 46% weapon damage plus an additional 33 to 42 as Holy damage.	new
Rank 8	60	20 Mana · Melee Range · Instant · 10 sec cooldown	An instant strike that causes 50% weapon damage plus an additional 40 to 53 as Holy damage.	new

Iron Creed (Protection row 6): Increases the threat generated by your Holy Strike ability by 30%. While Righteous Fury is active, Holy Strike also reduces your damage taken by 6% for 6 sec.
Shieldsworn (Protection row 7): Reduces the cooldown of your Holy Strike ability by 4 sec. Additionally, Holy Strike now strikes with your shield, triggering your active Holy Shield and Shield Specialization talents without consuming their charges or triggering their cooldowns, and allowing you to Block spells for 6 sec.
Sacred Arbiter (Retribution row 4): Increases the damage of your Holy Strike ability by 20% and causes it to refresh all Judgement effects on the target.

Source: beta client 1.60.1.70753. Spell ID 10333.