Does Anything Like number Exist?

As we use number or mailid for telephone number & email, does anything like Copy

The fax: URL is very similar to the tel: URL. The main difference is that in addition to ISDN subaddresses, telefaxes also have an another type of subaddress, see section 2.5.8.

Example:

<ahref="fax:+358.555.1234567">+358.555.1234567</a>

However, as per the comments below, RFC 2806 was obsoleted by RFC 3966 and you should just use the tel URI scheme:

The "tel" URI does not specify the call type, such as voice, fax, or data call, and does not provide the connection parameters for a data call. The type and parameters are assumed to be negotiated either in-band by the telephone device or through a signaling protocol such as SIP. This document obsoletes RFC 2806.

RFC 3966 was updated by RFC 5341 to formalize URI parameters and require them to be registered with IANA. I am including these here for the sake of completeness. They do not contain any additional information on fax devices.