В дозаторе находится гель для стирки.

Because after в meaning in/inside, Russian often uses the prepositional case to show location.

• дозатор = dispenser
• в дозаторе = in the dispenser

This is a location use, not motion. If there were movement into the dispenser, Russian would usually use the accusative instead.

Yes, here находится means something like is located / is found / is.

Russian often uses находиться when emphasizing where something is located. It sounds a bit more formal or descriptive than simply omitting the verb.

So:

• В дозаторе находится гель для стирки. = There is laundry gel in the dispenser / The dispenser contains laundry gel.

In everyday speech, Russians might also simply say:

• В дозаторе гель для стирки.

That is shorter and more conversational.

Гель is in the nominative case because it is the grammatical subject of the sentence.

Even though English may translate this as There is laundry gel in the dispenser, Russian treats гель as the thing being talked about:

• гель = subject
• находится = verb
• в дозаторе = location

So the basic structure is:

• [Where?] В дозаторе
• [What is there?] находится гель для стирки

Для стирки literally means for washing/laundry.

• для = for
• стирка = washing, laundry
• after для, Russian uses the genitive case
• so стирка becomes стирки

This is a very common pattern in Russian:

• средство для мытья = cleaner for washing
• машина для стрижки = machine for cutting
• гель для стирки = gel for laundry / laundry gel

Russian often prefers a noun + для + genitive structure where English might use an adjective.

Стирки is the genitive singular of стирка.

That happens because the preposition для always requires the genitive:

• для кого?
• для чего?

Examples:

• для дома = for the house/home
• для детей = for children
• для стирки = for washing/laundry

So стирка changes to стирки because of для.

Usually, no—not in the same natural way.

Russian есть does not work exactly like English there is / is in all contexts. In modern Russian, есть is often used for:

1. possession/existence
   • У меня есть машина. = I have a car.
2. emphasis that something exists/is available

But for location, Russian often either:

• uses no verb at all:
  • В дозаторе гель для стирки.
• or uses a verb like находится:
  • В дозаторе находится гель для стирки.

So находится is much more natural here than есть.

Yes, you can change it, but the emphasis changes.

Original:

• В дозаторе находится гель для стирки.

This starts with the location, so it answers something like What is in the dispenser?

Other possible orders:

• Гель для стирки находится в дозаторе.
  More neutral if you are talking about the gel itself.

• В дозаторе гель для стирки.
  Shorter, very natural in speech.

Russian word order is more flexible than English, but it is not random. The sentence often puts known information earlier and new or important information later.

Дозатор means a dispenser or dosing compartment/device, depending on context.

It can refer to:

• a soap dispenser
• a detergent dispenser
• a machine compartment that releases a measured amount

In a laundry context, дозатор often means the detergent compartment/tray in a washing machine, though in some contexts it could also mean a separate dispensing container.

So the exact English translation depends on the situation.

Because Russian often uses an abstract noun in the singular where English uses a broader phrase.

• стирка = washing, laundry, the act/process of washing clothes
• для стирки = for laundry / for washing

It does not mean one single wash only. It refers to the general purpose of the gel.

This is very normal in Russian:

• порошок для стирки = laundry detergent
• средство для уборки = cleaning product

So singular стирки is completely natural.

A more everyday version would often be:

• В дозаторе гель для стирки.

This is shorter and very natural in spoken Russian.

The version with находится sounds a bit more formal, technical, or explanatory, like something in instructions or a description. Both are correct; they just differ in style.