I want to hide my IP address on my email account when I send an email. How do I do it?
You mean you don't want your IP address found in the email header that a mail recipient could see, right?
The only way I know how to do this is to either use a VPN or log into a webmail account like Yahoo using TorBrowser. The resulting email header will have
an IP address but not
YOUR IP address.
There are webmail accounts which will hide your IP but they cost money.
https://www.raymond.cc/blog/hide-sender-ip-address-in-email-headers/
If you're using a standalone email program like Thunderbird, or Outlook, etc. then I'm not sure that it's possible to hide your IP address.