Using SharePoint Framework you can extend portals on Microsoft 365 and expose your apps where people work. Here are some resources to get you started.
SharePoint Framework is a development model for building apps on Microsoft 365. Originally, it started as a way to extend SharePoint portals. Nowadays, it allows you to also build apps for Microsoft Teams.
When you use SharePoint Framework to build your apps, you don't need to worry about hosting and auth. You can build your app using any client-side framework you want and easily deploy your app to your users.
Here is a list of resources to help you get started with building apps using the SharePoint Framework.
Introduction to customizing and extending SharePoint (learn module)
If you like a structured way of learning, this is the best place to start. This learn module takes you through the basics of what SharePoint Framework is, what kind of apps it allows you to build and how to do it. This module is a part of a larger learning path that allows you to get certified as a Microsoft 365 developer.
If you prefer a more hands-on approach, the SharePoint development tutorials and training are another great place to start. There are both written and recorded walkthroughs presenting the different aspects of building solutions using SharePoint Framework. They're kept up-to-date with the latest version of SharePoint Framework so it's a great resource for you to bookmark.
Once you're past the basics, the official SharePoint Framework is a great place to deepen your knowledge. In the docs you will find explanation of the different capabilities and how they work. The docs also offer prescriptive guidance on topics such as how to implement SharePoint Framework in development teams or what enterprise organizations should take into account.
Microsoft 365 has a vibrant community that supports each other in building apps on Microsoft 365. We share our experiences through regular community calls, offer guidance, record videos and build tools to speed up development. You can find everything we have to offer at aka.ms/m365pnp.
Over 250 million users work with Microsoft 365 and using SharePoint Framework is an easy way to bring your application to where people are. I'd encourage you to check out the resources I mentioned and give SharePoint Framework a try. And if you have any questions, don't hesitate to ask them on our community forums at aka.ms/m365pnp-community. Looking forward to hearing what you've built!