There are a number of ways to learn about Dynamics 365 and its family of products. Whether you are technical or business focused, a solution architect, developer, product owner, business analyst or QA/tester. Microsoft and the community have a wealth of material available for you to discover and explore.
Here are a few reference points I recommend for you.
LinkedIn Learning – Dynamics 365
Microsoft Virtual Academy – Dynamics 365
Microsoft Learn – Business Apps
Official Microsoft Dynamics 365 YouTube Channel
Dynamics 365 Community videos on YouTube
For MS Partners or Customers who have access to PartnerSource and CustomerSource you may find additional training material to meet your needs.
You can see further training details on Microsoft Docs regarding Dynamics 365 Training. For developers, Microsoft Docs also hosts a number of other useful resources.
Dynamics 365 Customer Engagement Developer Guide
Programming reference for Customer Engagement
Model-driven Apps Developer Guide
Common Data Service for Apps Developer Guide
if you choose to get certified in Dynamics 365 then read about this on the Microsoft Learning Website MCSA in Microsoft Dynamics 365