"work" can be a verb and a noun, but "job" is only a noun.
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If you are talking about employment:
I am looking for work. [noun]
I am looking for a job. [noun]
I have a job [noun]
{We don't say "I have work" meaning "I am employed"}
I am working [verb] two jobs [noun]
I work [verb] at home.
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If you are talking about a task, for example some things you need to do at home (cleaning, cooking, etc.):
I am doing some jobs [noun] around the house.
I am doing some work [noun] around the house.
Can you do a job [noun] for me?
{"Can you do work [noun] for me?" would mean employment or do some task probably for money}
{"Can you work [verb] for me?" would mean employment
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Some more examples:
I am working on my Chinese.
I don't work at the moment. {I have no job}
I don't have any work now. {I have a job but no work to do meaning I am employed but have no task to do}
What kind of job/work are you looking for?
This is a good job.
This hard job requires hard work. {"hard job" = difficult task, "hard work" = a lot of effort}