In order to manage your access policy, you will need to have the ‘All’ permission.
Access Policy Management is available in the Settings tab, new policies can be added and removed here. After making any changes you will need to save your changes in order for them to take effect.

To make use of this new policy, you will need to give this new claim to a user. Users can get permissions from multiple access policy statements.
Only users with the ‘All’ permission are able to assign claims referenced in the access policy to themselves or other users.
Warning
Any user that already has the claim in the access policy you are adding will be given the permission. This is also true if an access policy is removed, where any users with that claim will lose that permission.