I want to add a
Donate Bitcoin button to my website(s). I want to create a Bitcoin wallet with a permanent address for receiving donations. How would I do this?
Do not use a web wallet. Install Bitcoin Core or Electrum on your workstation and create a new receiving address, it will be valid permanently.
Re-using addresses is a privacy reduction but, there is no easily implemented alternative if placing a button on a web page unless you are tech savvy to setup a backend script.
Set a strong, secure password that you will never forget on your wallet to limit who can send payments. Ensure that you make a safe, secure and verified backup of your wallet and/or your wallet seed phrase and keep it up to date.