Click on "apply" on any host page, and if your project fits their criteria, they will approve it.
If you have a legal entity and bank account already, you can also set up your own fiscal host.
If you are an open source project with at least 100 stars on GitHub (or equivalent other website), you can apply to create your Collective under the umbrella of the Open Source Collective fiscal host.
To see your Fiscal Host options, go to edit Collective > Fiscal Host.
You can change the fiscal host of your Collective to a different host or your own host if you've set one up.
Zero the balance of your Collective
Go to edit Collective > Fiscal Host
Remove your current host
Select 'use your own host' or 'apply to an existing host
OR visit the page of the host you wish to join and click the "apply" button