How many days before i can encash cheque?

Unless the cheque itself says otherwise, you should be able to cash it immediately.

Even if it does have a later date on it, in the US, banks are not actually required by law not to cash "post-dated" cheques, though they generally do try not to. If you post-date a cheque, you should regard it as a polite reminder to the person you make the cheque out to not to cash/deposit it before then, not as an absolute barrier to them doing so.