Business plans support organizational decisions when they are used as a:

A well-crafted business plan serves as a living document that guides strategic initiatives, supports decision-making, and aligns cross-functional departments around common goals. It's not just a financial outline — it encompasses strategy, market positioning, risks, and HR alignment.

Extract from HRCI-aligned HR knowledge (Leadership and Strategy domain):

SPHR professionals are expected to “develop HR strategies aligned with the organization’s business plan and objectives.” A business plan functions as a guiding and supporting framework for budget planning, workforce planning, and strategic investment decisions across the organization.