تعریف و معنای "[fill] {one's} shoes"

What is the origin of the idiom "fill one's shoes" and when to use it?

The idiom "fill one's shoes" originates from the idea of stepping into someone's shoes, which means to take over someone's role or position. It has been in use since at least the early 20th century and used to describe a situation where someone takes over a role or position that was previously held by someone else.