The GDPR requires companies to inform their visitors about what happens to their personal data. They must do so in a privacy statement. An explanation in the Terms and Conditions is not legally valid.
You can choose how you would like to place this in your privacy statement. The following is a sample text that you could base your text on:
To measure B2B use of our website, we use the Leadinfo solution based in Rotterdam. This service shows us company names and addresses based on the IP addresses of our visitors. The IP address is not stored after use.