电话号码(diàn huà hào mǎ) - telephone number in Mandarin

电话号码 (diànhuà hàomǎ) is "telephone number", a compound of 电话 (diànhuà, "telephone, phone call") and 号码 (hàomǎ, "number, code"). It is the standard, formal way to ask for or give a number, and it is one of the first pieces of personal information any GCSE-style introduction dialogue asks for.

请告诉我你的电话号码 (qǐng gàosù wǒ nǐ de diànhuà hàomǎ), "please tell me your telephone number", is a set phrase worth learning whole, along with the reply pattern 我的电话号码是... (wǒ de diànhuà hàomǎ shì..., "my phone number is..."), followed by the digits read out one at a time.

In fast speech, Chinese speakers often shorten this to just 号码 (hàomǎ) when the context already makes clear that a phone number is meant, the same way English speakers might just say "number" rather than the full "telephone number".