Hi Nidhi,
If we can name everything on our own, that would be great. However it is not realistic. Those series are key to the table. There is no way you can have duplicate key.
Besides there is no benefit to name two different series by the same name but only confusion.
Unfortunately, INVoice and INVentory share the same first letters. We have to differentiate them by different names. A suggestion to you: Keep INV for invoice but IVT for inventory. Or you can think any better abbreviation.
Thanks,
Gordon