Some password managers, such as Bitwarden, allow you to automatically generate custom email-addresses, via other providers, for online services etc. Since DuckDuckGo-Email is privacy-oriented and free, I can recommend it. As it is currently not officially supported by DuckDuckGo to use third party generators you need some extra steps:
Firstly, go to DuckDuckGo.com/email and create a free account and redirecting address. Then copy your username here and enter the token you'll receive per email. Now just paste the shown API-Token into your password manager, and you'll never get tracked or spammed by anyone ever again.
We don't store any provided credentials (not even in server logs), but they must be sent to our servers and the Cloudflare proxy.