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

A well-craftedbusiness planserves as aliving documentthat guides strategic initiatives, supports decision-making, and aligns cross-functional departments around common goals. It'snot just a financial outline— it encompassesstrategy, market positioning, risks, and HR alignment.

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

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