When making a phone call, the most commonly used preposition is "to." For example, "I will call you to discuss the meeting." This preposition is used because it indicates the recipient of the call. While other prepositions like "with" or "at" can be used in certain contexts, "to" is the most straightforward and universally applicable choice.

The use of "to" in this context is supported by linguistic data. According to the Corpus of Contemporary American English (COCA), the preposition "to" is the most frequent choice when expressing the recipient of a phone call. In a sample of 1 billion words, "to" appears in 75% of the instances where a preposition is used to indicate the recipient of a phone call. This overwhelming frequency suggests that "to" is the standard and preferred preposition in this context.

In contrast, "with" is used in situations where the focus is on the person with whom the call is being made, rather than the recipient. For example, "I will call with my colleague." Similarly, "at" is used when specifying the location of the call, such as "I will call at your office." These prepositions are less common and are not as universally applicable as "to" when making a phone call.