If you use your travel document to enter back to the US you will invalidate your any visa status you had. If you still have O visa, continue to use it, don’t use EAD/Travel document unless you no longer have a visa.

I have O1 visa and I-485 is not approved but travel document is approved. how can we visit India without using travel document?

you don’t need travel document if you have a visa. You can reenter with that visa. forget about the travel document. Travel document is only needed if your I-485 is pending and you don’t have any other non-immigrant status.

thank you C A!