If you are the account holder, you can set a theme that will apply to all users in the account.
Before you can use a theme as an account-level theme, you have to grant the account authority user rights to link to your theme.
You can do this by creating a Permission manifest. This will need an item something like:
[
{
"user": "accounts",
"permission": [
"node-read-all-members",
"node-link",
"node-use-draft"
],
"node": "${theme}"
}
]
The user should be set to your account authority user. You can find this out by going to Settings, then Account manager, opening the More menu, and then looking for the owner of the page.
The permissions should be the three shown.
Set the node to ${theme), and then in the bindings section link the reference "theme" to your theme.
You will also need to grant users read access to your theme and all resources.
If you are creating a theme for use by other accounts, you will need to package your theme as a product.