Generating Key both with app and Google Sheets

[SYZ1]

Hi,
I have a sheets file where I keep a glossary of terms from various subject matters, their definition in another language etc. It is a very basic glossary. The ID in the Key column is automatically generated by the app, when I input data using the app.
But I also want to input bulk data on the sheets because it takes a long time to do it one by one on the app.
The problem is, when I use google sheets file to input data, I can’t generate keys for each item as the app can do.
How can I generate ID the same way the app does on Google Sheets, without disrupting the app?
Thanks