Starfinder Society Organized Play
The Character Options page explains which options are approved for Starfinder Society play, along with resource ownership rules (that is, what books you need).
Players can choose options their character has Access to in any books or supplements they own that are approved for Starfinder Society play. Players residing in the same household can share owned resources. Ownership of the Starfinder Player Core is not required to choose options from it. In that case, reference rules from the official online source, the Archives of Nethys.
Some options within the game have a rarity trait of uncommon, rare, or unique. Options without a rarity trait are considered common. Unless otherwise specified, you have Access to all common, uncommon, and rare options (subject to the normal resource ownership rules).
Standard
These options follow the standard rules as printed in their respective sourcebooks. If a character wants to take this option, they must meet all its prerequisites as usual. If the option is uncommon or rarer, they must also have access to the option. Characters can gain access in a variety of ways. They can gain access by virtue of their origin, religion, or their membership in certain organizations. Selecting certain common character options can give you access to other, rarer ones; for instance, a kasatha who takes the Kasathan Weapon Familiarity ancestry feat gains access to uncommon kasatha weapons. Specific boons—such as from the Achievement Points system or Chronicle Sheets—can also grant access to these options.
Limited
A limited option is rarer in Society play, but not unheard of. A limited option can be selected only if specifically allowed by a boon—whether from the Achievement Points system, a Chronicle Sheet, or another other option from a Starfinder Society source—even if the option is common or if the character meets the normal prerequisites or access requirements printed in the option's source.
Restricted
A restricted option is one that is not generally appropriate for all tables or conducive to the Pathfinder Society's shared campaign setting, such as a one-of-a-kind weapon, a horrific spell used by only the most evil magic-users, or player options that require high degrees of GM adjudication. Such options will generally be made available for Society Play in only a very few special cases, such as via boons given out as part of charity events, if at all.