Chapter 7: Spells Focus spells are automatically heightened to half your level rounded up, just like cantrips are. You can't cast a focus spell if its minimum rank is greater than half your level rounded up, even if you somehow gain access to it.
Source Player Core pg. 298 2.0
Focus spells are a special type of spell attained directly from a branch of study, from a deity, or from another specific source. You can learn focus spells only through special class features or feats, rather than choosing them from a spell list. Furthermore, you cast focus spells using a special pool of Focus Points—you can't prepare a focus spell in a spell slot or use your spell slots to cast focus spells; similarly, you can't spend your Focus Points to cast spells that aren't focus spells. Even some classes that don't normally grant spellcasting can grant focus spells, such as the ranger. The title of a focus spell's stat block says “Focus” instead of “Spell”, and the spell has the focus trait.
Casting any of your focus spells costs you 1 Focus Point. You automatically gain a focus pool the first time you gain an ability that gives you a focus spell. The maximum number of points in your pool is equal to the number of focus spells you know or 3, whichever is lower. This counts only spells that require Focus Points to cast. For example, a bard's composition cantrips don't count toward the size of the pool.
You replenish all the Focus Points in your pool during your daily preparations. You can also use the Refocus activity to pray, study, meditate, or otherwise reattune yourself to the source of your focus magic and regain 1 Focus Point. You can Refocus multiple times to regain multiple points, up to your pool's maximum.
Source Player Core pg. 298 2.0If you are a spellcaster, your focus spells are the same tradition of spell as the class that gave you the focus spell. A bard’s are occult, a cleric’s are divine, a druid’s are primal, a wizard’s are arcane, and a witch’s are determined by their patron.
Source Player Core pg. 298 2.0
If you get focus spells from a class or other source that doesn’t grant spellcasting ability, the ability that gives you focus spells also provides your proficiency for your spell attack modifier and spell DC, as well as the magical tradition of your focus spells. Though you can cast your focus spells, you don’t qualify for feats and other rules that require you to be a spellcaster or have a spellcasting class feature—those require you to have spell slots.
Source Player Core pg. 298 2.0
It’s possible, especially through archetypes, to gain focus spells from more than one source. If this happens, you have just one focus pool, counting all your focus spells to determine the points in your pool. You can spend any of your Focus Points on any of your focus spells. Likewise, when you Refocus, you get back a point as long as you follow the guidelines of any abilities that granted you focus spells. Having Focus Points from multiple sources doesn’t change the tradition of your spells; if you had both cleric domain spells and druid order spells, your domain spells would remain divine and the order spells primal. Similarly, you need to use the attribute modifier determined by the source of the focus spell
