Hello Shenal and thanks for using wazuh.
In the latest version of wazuh(v4.4.5) FortiOS 7 is unfortunately not listed as part of the supported fortigate versions. Nevertheless depending on the structure of the logs, you could copy and edit existing decoders and rules for v6.0 to make it match your firewall.
I'll be sending a memo to the core team requesting to include decoder and rules for FortiOS 7.0 in next release.
Regards,