after Download bitcoin core and get .dat file
so what is best software to open it (i use google and find many tools )also how can view it only (can exchange it from .adt to .txt
)?
also how open it with web wallet or only work with download version ?
Never open a wallet.dat with anything that isn't the native client for said wallet.dat file.
So for example if your wallet.dat is a Bitcoin wallet, then open it with Bitcoin Core or whatever client that generated that file.
If the wallet.dat is Litecoin's wallet.dat, use Litecoin Core... etc
Never attempt to open it with a text editor, online or anything else.