To implement SPF, you need to create an SPF record and publish it in your domain's DNS settings. The SPF record will include a list of authorized IP addresses that can send emails on behalf of your domain.
For DKIM, you need to generate a public-private key pair and publish the public key in your DNS records. Your email server must be configured to sign outgoing emails with the private key. Many email service providers offer tools and guides to help you set up DKIM.