I have never set up an encrypto password in copay. I want to send BTC but copay asks for encrypto password and cannot go any further. Please let me know what to do.
Regardless of how the password got enabled, once it is set, there is no way to access your coins without it, except by restoring the wallet using your backup phrase. So if you have your backup phrase, you can create a new wallet to access your coins. Choose the + button to create a new wallet and select "Import Wallet", and use the "Recovery Phrase" tab.
If you don't have the backup phrase, you are out of luck unless you can find the password. You might try to figure out how it got set:
Perhaps you set it and then forgot? Think about what password you might have chosen, or how you usually choose passwords.
Perhaps someone got access to your phone or computer, and set a password? Try to figure out who that might be, and ask them. Of course, it's possible they already spent all your coins.
Perhaps there's a bug in the Copay software that set a password without asking you. If you've ruled out all other possibilities, you could report it as a bug. But if so, it's hard to guess what the password might be, and I suspect you won't be able to recover your funds in this case.