Hi
WordPress comes with built-in functionality to manage user registrations. Go to Settings ? General page in your WordPress admin area and enable “Membership” – anyone can register.
The register form URL: https://your-website.com/wp-login.php?action=register
You can use some free plugin to add register/login for to your sidebar or with shortcode.
Some 3rd party plugins has own login/register options. Read the plugin documentation or contact the plugin authors. Example:
WooCommerce – Navigate to WooCommerce → Settings → Accounts & Privacy and Allow customers to create an account on the “My account” page.
How to create “My account” page for WooCommerce? https://docs.woocommerce.com/document/woocommerce-pages/
