An any profession that has the two options it is important to remember the Differance
License is issued by the state (it may or may not be required to practice your dicipline this depends on the state)
Certification is issued by the board of what ever it is that you study. This board usually represents what ever it is your studied but instead of like the state license which is for one state only, this is usually good for all 50 states this is why it is called a board cert. You took a test, passed and now you are board cert.
For example I am a licensed and board certified Nuclear medicine technologist in the state of Florida
I took my test that was issued by the board of nuclear medicine and past it..Now this board is recognized in all 50 states. However to practice nuclear medicine in the state of Florida I also Need a state license.
So i go to the dept that issues the license and show them that I am board certified because I pass my test...I pay my fee and get my state license...you usually dont take another test for a state licines you just show proof that you are board certified and then pay the state its dues in order for you to practice (you pay money they give you state license)
You alawys take your boards first in what ever diciple your in.
Then you go get a state license if that state requires it. Some states do not require A License to practice just board certified. However some do, in these states all you do is say hey check it out im board cert heres my money and they give you your state licenses.