https insert 443

It seems you are trying to add HTTP headers. You can use both local traffic policies or irules to achieve this. For more information about local traffic policies see:

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/local-traffic-policies-getting-started-12-1-0/1.html

Below you'll find an example of an iRule:

when HTTP_REQUEST {
    HTTP::header insert X-Forwarded-For [IP::remote_addr]
}

This article could also be useful. It compares BIG-IP LTM and NGINX configurations:

https://www.nginx.com/resources/deployment-guides/migrating-load-balancer-configuration-f5-nginx-plus/

To append 443 port at the end of Host header and insert real IP, use the following code:

when HTTP_REQUEST {
    HTTP::host "[HTTP::host]:443"
    HTTP::header insert X-Real-IP [IP::remote_addr]
    HTTP::header insert X-Forwarded-For [IP::remote_addr]
}