We replace the single handle delta faucet handle and now we can not get any hot water

In replacing the faucet you most likely disturbed some mineral built up in the pipe walls and now it's blocking the hot water port. Shut the water off and open up the valve. Remove the cartridge and the seats and springs. Now turn the water back on to flush out the valve and supplies. Reassemble and test. To tell you more I'll need a model number. Good luck, Tom