输入下面命令行

ssh-keygen 

默认回车得到下面的

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/{用户名}/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/{用户名}/.ssh/id_rsa
Your public key has been saved in /Users/{用户名}/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:。。。。。。。。。。。。。。。。。//此处省略

然后输入下面命令行

cat ~/.ssh/id_rsa.pub

得到生成的ssh-ras

然后复制到github或者其他仓库管理平台