I don't personally know anything about API, other than where the place is to click to request the key.
Click on your round "JK" avatar that appears probably (location may possibly vary depending on what type device you're on) just below the word "Support" in the upper right corner of TMDb's home page . A drop-down menu will appear. Click on "Settings". On a list that'll appear, click on "API". Near the bottom of the screen that then appears, you'll see "Request an API Key / To generate a new API key, click here."
Those steps should work.
PS: Since posting the prior portion of this comment, I've found the following Support thread that some of what's mentioned in particularly its latter portion may prove of interest/relevance to you:
Reply by genplant29
on June 22, 2017 at 12:50 AM
I don't personally know anything about API, other than where the place is to click to request the key.
Click on your round "JK" avatar that appears probably (location may possibly vary depending on what type device you're on) just below the word "Support" in the upper right corner of TMDb's home page . A drop-down menu will appear. Click on "Settings". On a list that'll appear, click on "API". Near the bottom of the screen that then appears, you'll see "Request an API Key / To generate a new API key, click here."
Those steps should work.
PS: Since posting the prior portion of this comment, I've found the following Support thread that some of what's mentioned in particularly its latter portion may prove of interest/relevance to you:
https://www.themoviedb.org/talk/58dcf6fc92514140ea00b09d
Reply by kodi
on June 24, 2017 at 7:09 PM
thank you