The following are sites to utilize for the official Microsoft Certifications for
PL-900, PL-400 and PL-200:
Microsoft Power Platform Fundamentals - for PL-900:
https://docs.microsoft.com/en-us/learn/paths/power-plat-fundamentals/
Introduction to developing with Microsoft Power Platform -
for PL-400:
https://docs.microsoft.com/en-us/learn/paths/intro-developing-power-platform/
Get started using Microsoft Dataverse - for PL-200:
https://docs.microsoft.com/en-us/learn/paths/get-started-cds/