You will need an old key to be able to do this! This key should have been made before May 2020.

IF YOU DON'T HAVE THIS KEY, THEN YOU CANNOT USE THIS INTEGRATION!

More info here: https://github.com/ErikKalkoken/slackApiDoc

Also, this has not been tested, since I don't have a legacy token anymore. Please let me know if something does not work.

This will allow you to create Slack accounts for your team.

Manifest

{
    "form": [],
    "exists": {
        "url": "https://slack.com/api/users.lookupByEmail?token={{TOKEN}}&email={{email}}",
        "method": "GET",
        "expected": "{{email}}"
    },
    "execute": [
        {
            "url": "https://slack.com/api/users.admin.invite?token={{TOKEN}}&email={{email}}",
            "data": {},
            "method": "GET"
        }
    ],
    "headers": {},
    "initial_data_form": [
        {
            "id": "TOKEN",
            "name": "Please put your token here",
            "description": "Your legacy Slack API token"
        }
    ]
}

Thanks to anchorhrg for the fixes!

Instructions

You cannot create a new token anymore. Use your token with the client scope for this. Add this token to the credentials.

Additional notes

YOU CANNOT USE THIS IF YOU HAVE NO TOKEN WITH THE CLIENT SCOPE!