Before when I heard people asked me, “What is your job?” I always replied like this “My job is an office worker.”
I think it must be influenced by Chinese language because I have found that the native speakers don’t usually say, “my job is an office worker.” Instead, they will say, “I am an office worker.” and it seems if I want to use “my job” to go with some job titles, I will have to put “as” in the sentence. For example,
My job is as an office worker.
However, I am not sure what I think is right.
There are two possibilities.  "job" refers to your job title, and  "job" refers to your duties.
Sam: What's your job (i.e., what's your job title)?
Pat: I'm a clerk.
Sam: What's your job (i.e., what are your duties)?
Pat: I file, type, and do other office duties.
The norm is,
Sam: What do you do?
Pat: I'm a clerk (. I work) for an insurance company.