Hi @William Ferreira,
Welcome to Microsoft Q&A and thanks for reaching out.
https://learn.microsoft.com/en-us/graph/auth-v2-user?tabs=http
- Register the app with Microsoft Entra ID.
- Request authorization.
- Request an access token.
- Use the access token to call Microsoft Graph.
- [Optional] Use the refresh token to renew an expired access token.
Best regards,