The Policy JSON accepts a block where the applicable actions are determined. Each Resource type has it’s own actions, but usually they are:

To determine which actions are applicable for the Policy, you can pass a string with a single action, or an array of actions. Also wildcards can be used, which means all possible actions.

Examples:

Use a wildcard to cover all possible actions:

...
"statement": {
  ...
  "action": "*",
  "resource": [...],
  "condition": {...}
  ...
}

Pass a string for a single action:

...
"statement": {
  ...
  "action": "create",
  "resource": [...],
  "condition": {...}
  ...
}

When using multiple actions, pass an array.

...
"statement": {
  "action": [
    "create",
    "update"
  ],
  "resource": [...],
  "condition": {...}
  ...
}