In Active Voice, a sentence emphasizes the subject, performing an action. In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the active voice and 'We' is the subject and 'Liza' is the object.
When we convert this sentence into passive voice, the subject 'We' of the active voice becomes the object 'us', the object 'Liza' becomes the subject.
The passive format "is + V3 (regarded)" should be used. This is the active and passive voice rule for the present simple tense.

The past perfect tense "had eaten" is transformed into the past perfect passive form "had been eaten."

If a verb requires an object after it, it is a transitive verb.
If a verb doesn't require an object after it, it is an intransitive verb.
For example:
The girls carry water to their village. (transitive verb) A light was shining. (intransitive verb)
There are certain verbs that are used in a particular pattern given below:
Subject + verb + noun/pronoun + present participle(-ing form).
Some of the verbs are given below:
Hate/love, stop/start, finish, enjoy, prefer, keep, rest, worth, propose, regret, etc.
Example: She hates going out in the night.
According to the rule and the example given above, 'has started bringing' will be used instead of 'has started bring' in the 2nd part of the sentence.

In Active Voice, a sentence emphasizes the subject, performing an action.
In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the active voice and 'Razia Sultana' is the subject and 'the northern part of India' is the object.
When we convert this sentence into passive voice, the subject 'Razia Sultana' of the active voice becomes the object, the object 'the northern part of India' becomes the subject.
The passive format "was + V3 (ruled)" should be used.
This is the active and passive voice rule for the past simple tense.
Hence, the correct sentence is 'The northern part of India was ruled over by Razia Sultana'