Hi Uday,
As Martin suggest, there is no special tool for migration from Oracle EBS to D365FO.
After exporting data from Oracle EBS, you can import data into D365FO using data management framework of D365FO. Please refer the document in Martin's reply.
The unit in which data is processed during data import/export in DMF is a data entity, such as Customers, Products, or Vendors, or a group of entities, such as master data, open stock, or balances.
A typical entity contains a set of business data that is stored in a set of normalized tables that have foreign key relationships among them. The import and export operations transform the data between the normalized tables and one corresponding flat (denormalized) table called a staging table.