When reading terms to find permission about adverting sites i saw it at 22th term:
{ The Service may provide, or third parties may provide, links to other World Wide Web sites or resources. Because InfinityFree has no control over such sites and resources, you acknowledge and agree that InfinityFree is not responsible for the availability of such external sites or resources, and does not endorse and is not responsible or liable for any Content, advertising, products or other materials on or available from such sites or resources. You further acknowledge and agree that InfinityFree shall not be responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with use of or reliance on any such Content, goods or services available on or through any such site or resource.
}
i can’t understand totally is it allowed or not?
You can advertise sites, but you and InfinityFree doesn’t assume any responsibility for the availability of their services and does not endorse and is not responsible or liable for that content available from these sites.
To answer your original question: it’s your website, and you decide what content is on it. If you want to place ads on your website, you’re free to do so.
The section you’re referring to isn’t related to using advertisements. Suppose that we would say “you could use ad provider XYZ”, and by following the instructions of provider XYZ, you break your website now or cause it to be broken in the future, then you can’t come to us and claim compensation because we told you to try provider XYZ.
It doesn’t say anything about whether you’re allowed to use third party services, it just says that we can’t take responsibility for it if you end up breaking something with those third party services.