You can either set them under the worker in your account, under its settings - make sure you encrypt
You can either set them under the worker in your account, under its settings - make sure you encrypt it so A) it’s secure and B) it’s retained between deployments. Alternatively, you can use Wrangler: https://developers.cloudflare.com/workers/wrangler/commands/#secret
Cloudflare Docs
Create, develop, and deploy your Cloudflare Workers with Wrangler commands.

