As of now, WhatsApp no longer supports Windows Phone. Official support ended on December 31, 2019, meaning you can't send or receive messages, or even log in to WhatsApp on a Windows Phone anymore.
If you're still using a Windows Phone and want to continue using WhatsApp, the best option is to switch to an Android or iOS device. WhatsApp allows chat backups and transfers, so you can move your data when upgrading your phone.
Unfortunately, due to the outdated OS and lack of app updates, Windows Phone is no longer viable for modern messaging apps.