Firewall - Fortinet Fortigate Firewall Policies Configuration

[@anuar.m.y]

so virtual ip = port forwarding,
i just wanted to know if a policy (any ipv4 policy) creates a statefull rule for each time a connection matches a policy.
for instance traffic going outbound entering the LAN and exiting to the WAN requesting a web site, if there is a policy to this traffic then does it remembers the connection or do i need a reverse policy written right under to match the returning traffic?
similar to the "est" keyword at the en of an ACL in cisco IOS ACLS.