They are documents that start out as Internet Drafts, become "Requests for Comments" (RFCs), and then after this consulting process (generally) get approved by the IESG as a standard.
Specifications that are intended to become Internet Standards evolve through a set of maturity levels known as the standards track. These maturity levels are "Proposed Standard", "Draft Standard", and "Standard"
A Proposed Standard specification is generally stable, has resolved known design choices, is believed to be well-understood, has received significant community review, and appears to enjoy enough community interest to be considered valuable. However, further experience might result in a change or even retraction of the specification before it advances. Usually, neither implementation nor operational experience is required
A specification from which at least two independent and interoperable implementations from different code bases have been developed, and for which sufficient successful operational experience has been obtained, may be elevated to the Draft Standard level.
A Draft Standard is normally considered to be a final specification, and changes are likely to be made only to solve specific problems encountered. In most circumstances, it is reasonable for vendors to deploy implementations of Draft Standards into a disruption sensitive environment.
A specification for which significant implementation and successful operational experience has been obtained may be elevated to the Internet Standard level. An Internet Standard (which may simply be referred to as a Standard) is characterized by a high degree of technical maturity and by a generally held belief that the specified protocol or service provides significant benefit to the Internet community.
Generally Internet standards cover interoperability of systems on the internet through defining protocols, messages formats, schemas, and languages. The most fundamental of the standards are the ones defining the Internet Protocol.
All Internet standards are given a number in the STD series. The first document in this series, STD 1, describes the remaining documents in the series, and has a list of proposed standards. Often, documents in the STD series are copies of RFCs or are a few RFCs collected together. For example, STD 8 defines the core of the telnet protocol and comprises RFCs 854 and 855.