Hi @Rahaman,
If you are creating a crowdsale for production, your solution should be appropriately tested, appropriately audited and you should check regulatory compliance prior to launch.
If you are using Crowdsale contracts with an ERC777, you need to check for any issues with reentrancy. See: Reentrancy After Istanbul
Rate
The rate is the conversion between wei and the smallest and indivisible token unit. So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
See the documentation for details: https://docs.openzeppelin.com/contracts/2.x/crowdsales#crowdsale-rate
Wallet
Is the wallet that you want to receive funds.
In a production system you may want to look at a multi-sig wallet (with signatories being hardware wallets) or a hardware wallet.
For testing you could use an address that you control
Token
This is the address of your token that you are selling in your Crowdsale
TokenWallet
This is the address holding the tokens that are being sold in the AllowanceCrowdsale.
An allowance needs to be approved to the Crowdsale.