Spellcasting Archetypes

Some archetypes grant you a substantial degree of spellcasting, albeit delayed compared to a character from a spellcasting class. A spellcasting archetype allows you to use Cast a Spell activations of items (such as scrolls, staves, and wands).

Spellcasting archetypes always grant the ability to cast cantrips in their dedication, and then they have a basic spellcasting feat, an expert spellcasting feat, and a master spellcasting feat. These feats share their name with the archetype; for instance, the sorcerer archetype's master spellcasting feat is called Master Sorcerer Spellcasting. All spell slots you gain from spellcasting archetypes are subject to the restrictions within the archetype. For instance, the eldritch archer archetype allows you to pick a spell list when you take its dedication feat. If you pick arcane spells, the archetype then grants you spell slots you can use only to cast arcane spells from your eldritch archer repertoire, even if you are a sorcerer with arcane spells in your sorcerer repertoire.

Basic Spellcasting Feat

Usually available at 4th level, these feats grant a 1st-rank spell slot. At 6th level, they grant you a 2nd-rank spell slot, and if you have a spell repertoire, you can select one spell from your repertoire as a signature spell. At 8th level, they grant you a 3rd-rank spell slot. Archetypes refer to these benefits as the "basic spellcasting benefits."

Expert Spellcasting Feat

Typically taken at 12th level, these feats make you an expert in spell attack modifier and spell DC and grant you a 4th-rank spell slot. If you have a spell repertoire, you can select a second spell from your repertoire as a signature spell. At 14th level, they grant you a 5th-rank spell slot, and at 16th level, they grant you a 6th-rank spell slot. Archetypes refer to these benefits as the "expert spellcasting benefits."

Master Spellcasting Feat

Usually found at 18th level, these feats make you a master in spell attack modifier and spell DC and grant you a 7th-rank spell slot. If you have a spell repertoire, you can select a third spell from your repertoire as a signature spell. At 20th level, they grant you an 8th-rank spell slot. Archetypes refer to these benefits as the "master spellcasting benefits."

Source: Pathfinder Player Core pg. 215