Here's a combined overview of work visas and work permits in 7 points.
1
Work visa grants entry, work permit allows legal employment within the country.
2
Embassy/consulate abroad issues work visas, host country's immigration issues work permits.
3
Work visa application can be complex, work permit process may be simpler.
4
Work visa tends to be shorter-term, work permit validity can match employment duration.
5
An expired work visa may require renewal for re-entry, a valid work permit often allows re-entry with a work visa.
6
Work visa tied to job/employer, work permit considers qualifications/labor market needs.
7
Some work visas authorize work directly, work permits often require a separate work visa.