In most cases, your current employer does not need to re-apply if they already got a Labour Market Impact Assessment (LMIA) to hire you.
For example, they do not need to re-apply if:
your work permit is still valid
you still work for the same employer (in a skilled job) as listed on your work permit
you work in a job listed as TEER Category 0, 1, 2 or 3 in the 2021 National Occupational Classification, and
that employer already got an LMIA to hire you before.
If you are working in Canada on a work permit that does not need an LMIA, your employer doesn’t need to get one to make your job offer valid.
When you create your Express Entry profile, you can show that you have a job offer. If we invite you to apply, you will need to submit a copy of the documents with your application.
But, if you plan to work for a different employer and want job offer points (or a valid job offer for the Federal Skilled Worker or the Federal Skilled Trades programs), your new employer will usually need to apply for a new LMIA (unless the job is exempt).
You must complete an Express Entry profile as the first step to immigrate to Canada permanently as a skilled worker.