Present Tense in Habitual Reported Speech

According to the British Council:

It isn’t always necessary to change the tense. If something is still true now ... we can use the present simple in the reported sentence.

Note the word necessary. In many contexts, it is still permissible to backshift the tense, even if something is still true now.

She said, "When do the banks close?"
1) She asked me when the banks closed.
2) She asked me when the banks close.

The first version (with a backshift) is definitely the best choice if we are talking about a conversation that took place many years ago, as bank closing times may have changed since then. The second version is better if you are talking about a conversation that took place last week, but you could also use the first version.

He said to me, "What does this word mean?"
1) He asked me what this word meant
2) He asked me what this word means

It is very unlikely that the word has changed its meaning since the conversation took place, so either version is acceptable. I think that I would go for the first version (with a backshift), though I cannot explain my preference in any way.

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Note that, unless you want to specify when you learnt about something "I have known about it for some time", you generally use know in the present tense: "I know that..."

I've known that when we write in Reported Speech and if the reporting verb is > past tense, we must change the tense.

It's possible that I'm not understanding you correctly, but as stated, that's not correct. When you're reporting what someone said, i.e. quoting someone, you leave the tense intact.

You only need to change it if it is you talking about what the other person said. And even then you only need to change it if the meaning can be misunderstood. From another question: 'my girlfriend told me she doesn't want me'. "Told" is past, but "doesnt want" stays in the present because presumably nothing has changed since then.

For the reported questions, the reported verb is ask. (Of course, there are more reported structures.)

The tense is not normally changed when using present simple. (For regular actions, routines or true facts.)
The question word is included when reporting.

— When do the banks close? She asked her friend.
— She asked her friend when the banks close.

In your second example, the tense of the reported question can be changed:

— What does this word mean? She asked her friend.
— She asked her friend what that word meant.