Here’s a few resources for you from Microsoft:
All general information regarding migrating to Azure stems from Azure migration and modernization center – https://azure.microsoft.com/en-us/migration/
The Strategic Migration Assessment and Readiness Tool (SMART Assessment) found at https://azure.microsoft.com/en-us/migration/cloud-migration/checklist/ can provide an assessment.
The Azure Migration and Modernization Program (https://azure.microsoft.com/en-us/migration/migration-modernization-program/) can provide referrals to Microsoft Partners that can assist you with your Migration.
Lastly, an eBook: