What is the origin of the idiom "cover for someone" and when to use it?

The idiom "cover for someone" likely originated from the concept of providing physical cover or protection, which gradually expanded to include the idea of assuming someone's responsibilities or offering support in their absence. The expression symbolizes the act of figuratively shielding or safeguarding someone, ensuring that their actions or absence are managed or concealed effectively. It is often used in work settings when colleagues or teammates provide support and take on tasks to ensure continuity when someone is absent or unable to fulfill their obligations.