The owner of the farm have the option "Manage farm" on the menu. Members of the farm do not have this option.
Under "manage farm" you see the members of the farm and you can invite users to my.luda.farm and your farm.
You can choose between sending the invite to mobile numbers or emails.
If the user does not already have an my.luda.farm account it needs to be created first and then accept the invite to your farm.