Я користуюся передплатою.

The dictionary form is користуватися.

In this sentence, користуюся is:

• 1st person singular
• present tense
• from the verb користуватися = to use, to make use of

So:

• я користуюся = I use / I am using
• ти користуєшся = you use
• він/вона користується = he/she uses

-ся is a very common Ukrainian verb ending/particle, often called the reflexive marker.

With користуватися, it is part of the normal verb. You usually cannot just remove it and keep the same meaning.

So the standard verb is:

• користуватися = to use

Even though -ся originally has a reflexive background, here you should mostly learn the whole verb as one unit: користуватися + instrumental case.

Because користуватися requires the instrumental case.

The base form is:

• передплата = subscription

But after користуватися, it changes to instrumental singular:

• передплатою

This is a very important pattern:

• користуватися телефоном = to use a phone
• користуватися словником = to use a dictionary
• користуватися нагодою = to take advantage of an opportunity
• користуватися передплатою = to use a subscription

For feminine nouns ending in -а, the instrumental singular is often -ою:

• книга → книгою
• машина → машиною
• передплата → передплатою

They are similar, and in many contexts both can mean subscription, but they are not always identical in tone or usage.

A useful rough guide:

• передплата often suggests a paid subscription, sometimes a bit more formal
• підписка is also very common, especially in modern digital contexts

Depending on context, Ukrainians may say either one. But in your sentence, передплата is completely natural.

Ukrainian has no articles like a or the, so the sentence by itself does not specify that.

Я користуюся передплатою could mean:

• I use a subscription
• I use the subscription
• I use my subscription

Context tells you which one is meant.

If you want to make my explicit, you can say:

• Я користуюся своєю передплатою = I use my subscription

Yes. Very often you can.

Because користуюся already shows I, Ukrainian often drops the pronoun when it is not needed:

• Користуюся передплатою. = I use/am using a subscription.

Including Я can add:

• emphasis
• contrast
• clarity

For example:

• Я користуюся передплатою, а він — ні. = I use a subscription, but he doesn’t.

It can mean either one, depending on context.

Ukrainian present tense often covers both:

• I use
• I am using

So Я користуюся передплатою can describe:

1. a habit or general fact

   • I use a subscription

2. something happening now

   • I am using a subscription

If you want to make right now clearer, you can add a word like:

• зараз = now

Example:

• Я зараз користуюся передплатою. = I’m using the subscription now.

The usual stress is:

• Я користу́юся передпла́тою.

A rough English-style pronunciation guide:

• ya ko-rys-TOO-yu-sya pe-red-PLA-to-yu

A few tips:

• я sounds like ya
• и is not exactly English i; it is a central vowel, a bit like a short relaxed ih
• ю in -тую- gives a yu sound
• -ся here sounds roughly like sya

You might hear or understand that, but Я користуюся передплатою is the more natural choice for using a subscription/service/resource.

The verb використовувати means to use, to employ, to utilize, but it often feels more like handling something as an object or using it for a purpose.

So:

• користуватися передплатою = the normal, idiomatic way to say use a subscription
• використовувати передплату = possible in some contexts, but less natural here

A good rule:

• for tools, services, systems, subscriptions, transport, dictionaries, websites, etc., користуватися is very often the best choice

For a negative sentence, add не before the verb:

• Я не користуюся передплатою. = I don’t use a subscription.

For a yes/no question, Ukrainian often just uses intonation:

• Ти користуєшся передплатою? = Do you use a subscription?

You can also use чи for a more explicit question:

• Чи ти користуєшся передплатою?
• Чи користуєшся ти передплатою?

Both mean:

• Do you use a subscription?

No, Ukrainian word order is fairly flexible.

The neutral order here is:

• Я користуюся передплатою.

But you can move things around for emphasis:

• Передплатою я користуюся.
  This emphasizes the subscription

• Я передплатою користуюся.
  Also possible, with a slightly marked or contrastive feel

So the basic meaning stays the same, but the focus can shift.

Then you would normally use a different structure.

Common options are:

• У мене є передплата. = I have a subscription.
• Я маю передплату. = I have a subscription.

If you want to say I subscribed, that is different again:

• Я оформив передплату. = I took out a subscription.
• Я оформила передплату. = same, said by a woman

So:

• Я користуюся передплатою = I use/am using a subscription
• У мене є передплата = I have a subscription