A Standards Track BIP describes any change that affects most or all Bitcoin implementations, such as a change to the network protocol, a change in block or transaction validity rules, or any change or addition that affects the interoperability of applications using Bitcoin.
An Informational BIP describes a Bitcoin design issue, or provides general guidelines or information to the Bitcoin community, but does not propose a new feature. Informational BIPs do not necessarily represent a Bitcoin community consensus or recommendation, so users and implementors are free to ignore Informational BIPs or follow their advice.
A Process BIP describes a process surrounding Bitcoin, or proposes a change to (or an event in) a process. Process BIPs are like Standards Track BIPs but apply to areas other than the Bitcoin protocol itself. They may propose an implementation, but not to Bitcoin's codebase; they often require community consensus; unlike Informational BIPs, they are more than recommendations, and users are typically not free to ignore them. Examples include procedures, guidelines, changes to the decision-making process, and changes to the tools or environment used in Bitcoin development. Any meta-BIP is also considered a Process BIP.
Стандартные в этой иерархии стоят на первой ступени - они описывают любые изменения биткоина, информационные следуют за ними - им следовать не обязательно -"users and implementors are free to ignore Informational BIPs or follow their advice."
BIP 39 - стандартный, BIP 32 - информационный
https://en.bitcoin.it/wiki/BIP_0123