Vault serves as a dedicated storage point for secret values such as the signing keys for repos, authentication tokens to 3rd party services, and as an authentication nexus between short lived API tokens and long lived NetAuth credentials.
To log into vault you will need a NetAuth account, and may then log in using the following command:
export VAULT_ADDR=https://vault.voidlinux.org vault login -method=ldap username=<you>
This will prompt you for your password and request a vault token valid for a maximum of 12 hours. You don't need to do anything to actually use the vault token, all software that is Vault aware will natively pick up your authority. After the 12 hours has expired you will need to log in again to refresh your session.
If you wish to explicitly revoke your token, for example logging off
for the day, you may do so with the command
vault token revoke -self
which will request immediate revocation.