אם היה לי זמן עכשיו, הייתי ממלאת את הטופס וחותמת על המסמך.

Because Hebrew usually expresses to have with יש / היה + ל־ rather than with a separate verb meaning have.

So:

• יש לי זמן = I have time
• היה לי זמן = literally there was time to me, but naturally I had time

In this sentence, זמן is the thing that exists for me, so Hebrew says if there were time for me now, not if I had with a separate verb like English does.

Because this is a present unreal / hypothetical condition.

English does the same thing:

• If I had time now, I would...

Even though it is about now, English uses had, which looks past. Hebrew also uses a past form here:

• אם היה לי זמן עכשיו = If I had time now

So the past form does not mean the situation happened in the past. It signals that the condition is contrary to fact or hypothetical.

Hebrew often forms this kind of conditional with:

• הייתי
  • participle

So:

• הייתי ממלאת = I would fill
• הייתי ... חותמת = I would sign

Literally, הייתי means I was, and ממלאת / חותמת are participle forms. But together, in the right context, they express would.

A very common pattern is:

• אם ... היה / היו ... , הייתי + participle
• If ..., I would ...

Because the speaker is feminine.

In the singular first person, הייתי stays the same for both men and women, but the participle shows gender:

• feminine: הייתי ממלאת ... וחותמת
• masculine: הייתי ממלא ... וחותם

So if a man were speaking, the sentence would be:

• אם היה לי זמן עכשיו, הייתי ממלא את הטופס וחותם על המסמך.

In the past tense of להיות (to be), first person singular is the same for both genders:

• אני הייתי = I was

So Hebrew does not distinguish masculine vs. feminine here.
The gender difference appears in the participles:

• ממלא / חותם = masculine
• ממלאת / חותמת = feminine

This is very normal in Hebrew: sometimes the verb form itself does not show gender, but another word in the sentence does.

Because את marks a definite direct object.

Here:

• את הטופס = the form as a direct object of ממלאת
• הטופס is definite because of ה־ (the)

So Hebrew uses את.

But in:

• חותמת על המסמך

the noun המסמך is not a direct object. It comes after the preposition על (on). Since it is part of a prepositional phrase, there is no את.

So:

• ממלאת את הטופס = fills out the form
• חותמת על המסמך = signs on the document

Because the verb לחתום usually takes the preposition על when you mean sign a document.

So Hebrew says:

• לחתום על מסמך = to sign a document

Even though English says sign the document, Hebrew uses the structure sign on the document.

This is just a normal verb-preposition pattern that learners need to memorize.

Because one הייתי can apply to both participles:

• הייתי ממלאת את הטופס וחותמת על המסמך

This means:

• I would fill out the form and sign the document

Hebrew does not need to repeat הייתי before the second verb if the meaning is clear.

You could repeat it for emphasis or clarity:

• הייתי ממלאת את הטופס והייתי חותמת על המסמך

But that is less economical and usually unnecessary.

Yes. By itself, הייתי + participle can sometimes mean a habitual past idea, like I used to fill.

For example:

• כשהייתי עובדת שם, הייתי ממלאת טפסים כל יום.
• When I worked there, I used to fill out forms every day.

But in your sentence, the אם clause makes the conditional meaning clear:

• אם היה לי זמן עכשיו, הייתי ממלאת...
• If I had time now, I would fill...

So here the meaning is definitely would, not used to.

Because היה agrees with זמן, which is a singular masculine noun.

• זמן = masculine singular
• so: היה זמן

If the noun were feminine, you would get הייתה instead:

• אם הייתה לי אפשרות... = If I had an opportunity...

If it were plural, you would use היו:

• אם היו לי עוד כמה דקות... = If I had a few more minutes...

Yes, but it would mean something different.

• אם יש לי זמן עכשיו, אמלא את הטופס ואחתום על המסמך. = If I have time now, I will fill out the form and sign the document.

That is a real possibility.

But your original sentence:

• אם היה לי זמן עכשיו, הייתי ממלאת את הטופס וחותמת על המסמך.

means the speaker is imagining a situation that is not actually true right now. It is more like:

• If I had time now...
• implying but I don’t

So the choice between יש and היה changes the kind of condition:

• אם יש לי... = real/open condition
• אם היה לי... = unreal/hypothetical condition

עכשיו anchors the hypothetical situation in the present moment.

Without עכשיו, the sentence would still mean something like:

• If I had time, I would fill out the form and sign the document.

With עכשיו, it becomes more specifically:

• If I had time now...

That helps show that the speaker is talking about a present lack of time, not a general life situation.

Yes. The verb למלא means to fill, and with forms it naturally means fill out.

So:

• למלא טופס = to fill out a form
• ממלאת את הטופס = filling out / would fill out the form

Hebrew does not need a separate particle like English out here. The basic verb למלא already works naturally for forms.