With the New user access setting, you can choose whether new users will be Members or Limited Members when they join your space. If you choose Limited Members, you can also choose the kits they will have access to.
You can find this setting under the Access Controls section of the Settings page.
The setting will show the current role and number of kits it is set to underneath its' title and description. Click on the "Edit" button to change this. Once you're done making your edits, you'll see them reflected back on the settings page.
A few important things to note
This will apply to any new user joining your space through a join link, with an approved email or through SSO.
This setting was previously "Manage join link". It now applies to more than just the join link, so it became its' own setting!