Condition for a relation to follows axiom of completeness is that any(mind it any) two bundles taken into consideration satisfies that relation.
Let us take an example of a single bundle say x1.
now x1 is weakly preferred to x1(itself).
but we can't say that x1 is strictly preferred to x1(itself).
Hence "weakly preferred relation" follow axiom of completeness while "strict preference" do not.
I have a doubt. What about an indifference relation ? This does satisfy an indifference relation. We can say that the consumer is indifferent between X1 and X1. So going by your explanation, this should mean that an indifference relation is complete which is not true.
Mind it I said any two bundles. Take two different bundle x1 and x2 this time.
will x1 will be indifferent to x2 always??
so indifference relation does not follow axiom of completeness.