By default when MPLS and LDP is configured in a cisco IOS/IOSXR and some IGP.

If I forward a packet toward internal IP. Router will use MPLS to get destination. When show the routing table I only can see the route learnt by the IGP but not LDP. LDP is prefered vs IGP because of the administrative distance? Or there are other reasons

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Welcome to Network Engineering!
LDP is not a routing protocol, so Administrative Distance does not apply.

It's not clear from your question, but how the router forwards depends on what kind of packet it is. If the packet is MPLS, the router will use the label stack to determine where to forward. If the packet is unlabeled, it will use the routing table.

If the router is configured as an ingress router, then it will encapsulate the packet with a label and forward it based on that.

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