Tax Year Prior to 2020: I have been doing and online certification class and would like to know if it applies to the education tax credit

Most certification courses do not qualify. That said, you can check out this link to the US Department of Education Database of Accredited Schools to see if your school is listed there.  If it’s there, you are good to go, according to the IRS. 

An eligible educational institution is any college, university, vocational school, or post-secondary educational institution eligible to participate in a student aid program administered by the US Department of Education.  Virtually all accredited public non-profit, proprietary (privately-owned profit-making) post- secondary institutions.

Here is a link with more information about Education Tax Benefits that you may want to read:

https://ttlc.intuit.com/replies/3301953