Hi @Garima Sharma ,
I would suggest you use SharePoint Migration Tool which is the official tool recommended by Microsoft. The SharePoint Migration Tool (SPMT) is a free and easy to use migration solution to help you migrate content from on-premises SharePoint sites to Microsoft 365.
SPMT supports migration to SharePoint, OneDrive, and Teams from:
SharePoint Server 2010, 2013, and 2016
SharePoint Foundation 2010 and 2013
For more information please refer to:
Overview of the SharePoint Migration Tool (SPMT)
The contents in SharePoint Online are stored in servers provided by Microsoft, just check this article for details about plan your sites:
SharePoint Server team sites Migration Guide
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