Geo-fencing for block and allow one country

Hello Khan, 

Please follow below steps to configure geo-fencing in F5 AFM to allow access only from the USA and block all other countries:

1. Log in to the F5 Configuration Utility.
2. Navigate to Security > Network Firewall > Policy List.
3. Create a New Firewall Policy.
4. Define Rules for the Policy:
   • Create an Accept rule for Source: Geolocation and select United States.
   • Create a Reject/Drop rule for Source: Geolocation and select Not in United States.
5. Save and Apply the Policy to the relevant virtual servers.

i have not found Not in united stated 

Please follow the steps outlined in the article below.
https://clouddocs.f5.com/training/community/firewall/html/class1/module1/lab4.html#create-the-geo-restrict-firewall-rule-list-and-firewall-policy

i am facing problem how to block all and all only one country  

It is not AFM but one work around is to make an Irule that would drop all outside connections. Something like:

when HTTP_REQUEST {

   if {  [whereis [IP::client_addr] country] != "US" } {

   drop

   }

}

This would drop all not united states based IPs.