I generated btc address and put some coins into it. Now I want to send coins to another address. I can't find any infomation about how I can do it. I don't have wallet, I only have address: public key and private key.
If you have your private key, you are able to import it into a wallet and send the coins from there. The trustless way to do this would be to start your very own Bitcoin and user the Import Private Key RPC call. You then would be able to use the Send To Address RPC call to send the coins.
Depending on your necessary security level, it may be easier to just use an online wallet service like BTC.com. They have instructions available for importing private keys as well: https://help.btc.com/hc/en-us/articles/360002934354-How-do-I-import-my-private-key-into-the-wallet-