When someone begins a new career path, you can say "congratulations on" or "congratulations for" your new job. Both are correct.

When someone begins a new career path, you can say "congratulations on your new job" or "congratulations for your new job". They both are correct. For example:

Congratulations on/for getting your dream job, Sarah.

Congratulations on/for your new position.

More examples:

Congratulations for scoring a new job.

Congratulations on seizing control of your career.

Congratulations on landing your new job.

In general, "congratulations" is more common with "on"; for example, you can say: "congratulations on your marriage (or wedding)", "congratulations on your new baby", "congratulations on your graduation", or "congratulations on your achievement".

Congratulations on your wedding!