There are several ways to create a keypair identifier for Solana. The first we will see is CLI generation for development purposes. First, you will need to install it with this command:
sh -c "$(curl -sSfL https://release.anza.xyz/stable/install)"
Then, create a keypair with solana-keygen new and configure it to Devnet (the network for testing in a development environment) with solana config set --url devnet. You can see your address or public key with the command solana address.
To make it easier, you can get the Phantom extension or other wallet apps to do this automatically. These apps store the private key in the browser's storage, which is generally more secure than the CLI method because the CLI stores the private key in a plain config.json file.