isn't there a simple site where you can input few data and it gives you an estimated transfer fee? I want to know how much it costs to transfer 10 Bitcoin from 1 wallet to another wallet.
Sites will generally give a suggested fee rate, rather than an absolute fee. The fee rate should be in the format of sats/vbyte. This is how much satoshi you will pay for each virtual byte of space your transaction takes up. The number of virtual bytes a transaction takes up is dependent on the number of inputs, the number of outputs, the exact type of those inputs and outputs (legacy, segwit, etc), and a few other factors.
For example, if your transaction was 2000 vbytes and you paid 1 sat/vbyte, you would pay 2000 sats. Your transaction would be right at the bottom of the current mempool, since miners care more about the fee rate than the absolute fee.
If your transaction was 250 vbytes and you paid 8 sats/vbyte, you would also pay 2000 sats, but this time your transaction would be much nearer the top of the current mempool.
A transaction moving 10 bitcoin could involve 1 input and 1 output and therefore be as low as 110 vbytes in size, or it could involve 100 inputs (or more) and be thousands of bytes in size. It all depends on across how many inputs that 10 bitcoin is spread.