# Working with Phone Numbers

When sending phone numbers into CrowdPower, it is best to use the E.164 standard. E.164 is the international telephone numbering plan that ensures each device on the Public Switched Telephone Network (PSTN) has a globally unique number. This number makes sure phone calls and text messages can be correctly routed to phones in different countries.

E.164 numbers are formatted: **\[+] \[country code] \[area code and number]** and can have a maximum of 15 digits.

An example of a US number in E.164 format is: **+15165555555**


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.crowdpower.io/resources/working-with-phone-numbers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.