DO == Noun or verb?

Martha Washington understood my signs, and I seldom had any difficulty in making her do just as I wished.

I read that on a book. why do is in present tense?

It is a verb, and it is the base of the infinitive. You can tell it isn’t a finite verb, because it is preceded by an object rather than a subject pronoun.

It is not far removed from this:

I forced [color=red]him to do his homework.

So the " do " is wrongly used in the sentence that I posted? Then, how the correction look like, any suggestion?

No, I did not say it was wrongly used. On the contrary, I just explained what it was. It is definitely correct.

So what is the different :

do 0R to do

I forced him “to do” his homework.
I forced him “do” his homework.

The verb “force” requires the full infinitive, whereas “make” requires only the base. I pointed out the similarity so you would see “do” is not a finite verb in the present tense in your example.

Hi, Mordant
based on your reply, I think the sentence should be :
I seldom had any difficulty in making her to do just as I wished.

to do (not do) . what do you think the sentence above, Mordant ?