Hi there, @kaliappan.
At this time, merging different company files into one isn't available. However, you have the option to import lists or transactions from one company to another.
You can check this article to find out more about the import using IIF files: Tasks you can do with IIF files.
These files make it easier to transfer data to and from different platforms. To get started, you can refer to this article for some samples: IIF Overview: import kit, sample files, and headers.
If you have follow-up questions about the import, do let me know. I'm here to help.