A oficina fica perto de casa.

Because oficina is a feminine noun in Portuguese, so it takes the feminine singular article a.

• a oficina = the workshop / the repair shop
• uma oficina = a workshop / a repair shop

Like many nouns ending in -a, it is feminine, though gender in Portuguese is something you often just have to learn with the noun.

Usually, no. This is a very common false friend for English speakers.

In Brazilian Portuguese, oficina usually means a workshop, repair shop, garage, or sometimes a studio/workspace, depending on context.

If you want office in the English sense, the usual word is escritório.

So:

• oficina mecânica = mechanic’s shop / garage
• escritório = office

Here, fica means something like is located or is situated.

The verb ficar has several meanings in Portuguese, including:

• to stay
• to become
• to be located

In this sentence, it is the location meaning:

• A oficina fica perto de casa.
• literally: The workshop stays near home
• natural English: The workshop is located near home

This use of ficar is extremely common when talking about where places are.

Fica is the 3rd person singular, present indicative form of ficar.

It matches the subject a oficina, which is singular.

A few present-tense forms of ficar are:

• eu fico = I stay / I am / I become
• você fica = you stay / are / become
• a oficina fica = the workshop is located
• eles ficam = they stay / are located

So grammatically, fica agrees with a oficina.

Because perto normally takes the preposition de before the thing you are near.

So you say:

• perto de casa = near home
• perto do banco = near the bank
• perto de mim = near me

This is just the normal pattern in Portuguese: perto + de + noun/pronoun

Because casa often appears without an article when it means home in common expressions.

So these are very natural:

• em casa = at home
• de casa = from home / of home, depending on the expression
• para casa = home

In perto de casa, the meaning is near home.

If you say perto da casa, that usually means near the house, referring more to a specific building.

So the difference is often:

• perto de casa = near home
• perto da casa = near the house

Here it sounds more like home.

That is because casa without an article in expressions like this often has the broader, more personal sense of home, not just the physical building.

So:

• perto de casa = near home
• perto da casa = near the house

English sometimes uses house and home differently, and Portuguese does something similar here through the presence or absence of the article.

It depends on the context.

Very often, perto de casa means near my home if the speaker is talking about their own situation. But it could also mean near your home or near his/her home if that is already clear from the conversation.

Portuguese often leaves this kind of detail to context instead of spelling it out every time.

Yes, but they are not all equally natural in the same way.

• A oficina fica perto de casa = the most natural and standard way to say where a place is located
• A oficina está perto de casa = possible, but less neutral for basic location
• A oficina é perto de casa = understandable, but less natural in this kind of sentence

In Brazilian Portuguese, ficar is very commonly used for the location of places:

• O banco fica na esquina.
• A escola fica longe.
• A farmácia fica perto daqui.

So if you want the safest, most natural choice, use fica.

In normal Portuguese, no. A singular countable noun like oficina usually needs an article or another determiner.

So you would normally say:

• A oficina fica perto de casa. = The workshop is near home.
• Uma oficina fica perto de casa. = A workshop is near home.

Without a or uma, it sounds incomplete in ordinary speech, unless it is some kind of headline, label, or very telegraphic style.

The normal, neutral order is:

A oficina + fica + perto de casa

This is the most natural order for a simple statement.

You may sometimes hear more marked versions, such as:

• Perto de casa fica a oficina.

That is possible, but it sounds more emphatic or stylistically marked. For a learner, A oficina fica perto de casa is the best basic pattern to remember.