In website headers you can link to your chosen licence, e.g. in the case of creative commons:
<link rel="license" href="http://creativecommons.org/licenses/by/4.0/" />Likewise there's the Dublin core standard version:
<meta name="DC.rights" content="© 2024 Example Company" />
<meta name="DC.license" content="http://creativecommons.org/licenses/by/4.0/" />Schema.org
<script type="application/ld+json">
{ "@context": "https://schema.org",
"@type": "CreativeWork",
"copyrightHolder": {
"@type": "Organization", "name": "Example Company"
},
"license": "http://creativecommons.org/licenses/by/4.0/"
}
</script>