Software architecture is used to organize and conceptualize a system like a blueprint of a building, a bridge, or any other kind of structure.
Conceptually, "What" and "Where" are included, but "How" is not.
Software design is responsible for the code-level design, what each model is doing, the class scope, the functions, purposes, structure and class relation, etc.
Software design focuses on how the software will be built. But, software architecture identifies the components and elements that need to be included in the software.
Conceptually, "How" is included.
Software Architecture vs Software Design
Software architecture is primarily concerned with what the components and relationships are, and software design focuses on how the components interact.