Hi, @Ahmet Darci Welcome to Microsoft Q&A thanks for posting your question.
I understand that you want to import two CSV files, vertex.csv and edges.csv, into Azure Cosmos Graph DB
You can use BulkExecutor specifically written for Gremlin API, refer https://learn.microsoft.com/en-us/azure/cosmos-db/gremlin/bulk-executor-dotnet
It is available in .Net and Java as well
Regards
Geetha