Privacy Policies and Terms of Service agreements are both vital components of any website or mobile app. However, they each serve very different purposes and provide very different types of important information to visitors to website or mobile app. The Privacy policy is consent to the use and processing of personal data. The terms of Service is an agreement on the terms of use of your site as a service for the provision of certain services.

As here is the title of two documents, I think they should be translated explicitly and these features should have the same names as on other platforms (it can be more familiar to new users) and their meaning should be obvious. "Privacy" is translated as "конфиденциальность" (privacy in terms of social networks and messengers means confidentiality). "Policy" has its direct translation - "политика" (as the administration of Telegram sets the privacy policy for users). "Terms" has its direct translation - "условия" (as future users have to know, for instance, what they can do and why they can be banned). "Service" is translated as "использование" (using (terms of using)) as the meaning of this word is about providing people with something they are going to use.