when a user uses online wallet like blockchain.info it gives him more than 1 address like
new address : 13nYYLitRDrSuUfFRThYZaZQeDpx618cYs / first address :1AFR9EQ9cFiaFhs5gE1vFE4foPDghX5x48
How to know those two address from the same wallet?
what’s the right word on a google search to get more about this topic?
That's one of the disadvantages of using a wallet like blockchain.info, you can't see all of the pregenerated receiving adresses etcetera, ( as far as i know), and neither are your private keys easily accessible.
What you can do is put the adress into something like
https://www.walletexplorer.com/wallet/0729db5ddd132004/addresses, to see from which wallet it is part of.
Note that this will only work when the adress has ATLEAST 1 incoming TX/ confirmed TX.
Newly generated adresses won't show up with the corresponding wallet.
you could manually create new adress using this guide,
https://support.blockchain.com/hc/en-us/articles/207746403-Addresses