How deep do you spread wood chips? https://i.postimg.cc/hPpMZsVC/chips.jpg

A tree trimming crew asked if they could leave "wood chips" where I hadn't
expected such a huge pile. I'll need to spread them out a bit.

How deep on existing soil & wild grass would you put wood chips?

I'll have to wheelbarrow them and spread them out with a rake.
I just want to know how deep to spread them.