Hi,

In the email template, you must send a dynamically link e.g.: http://localhost:8069/web/reset_password?token=qvNvtQUjoB4oiOBrWcjs&db=odoo12e_english and just add a controller to check when an user click the button in his inbox email.

e.g.:

<a href="${object.signup_url}" style="background-color: #875A7B; padding: 8px 16px 8px 16px; text-decoration: none; color: #fff; border-radius: 5px; font-size:13px;">
    Accept invitation
</a>

@http.route('/web/reset_password', type='http', auth='public', website=True, sitemap=False)
def web_auth_reset_password(self, *args, **kw):
    # Your code here...

Best regards!