Escreve a tua morada no envelope, por favor.

Escreve is the imperative form used to give a command or instruction to one person in an informal way.

Here it means something like:

• Write your address on the envelope, please.

In European Portuguese, when speaking to tu informally, the command for many verbs looks like the present tense form without the final -s:

• tu escreves = you write
• escreve! = write!

So escreve is the natural informal command here.

It is addressed to tu.

You can tell because of two clues:

• escreve = imperative for tu
• tua = your used with tu

So the speaker is talking to one person informally.

If it were formal, you would usually get:

• Escreva a sua morada no envelope, por favor.

That would be the você / formal version.

Tua means your when speaking to tu.

It agrees with morada, which is a feminine singular noun.

So:

• teu = your (masculine singular)
• tua = your (feminine singular)
• teus = your (masculine plural)
• tuas = your (feminine plural)

Because morada is feminine singular, Portuguese uses tua:

• a tua morada = your address

In Portuguese, possessives are very often used with the definite article, especially in European Portuguese.

So a tua morada is completely normal and very natural.

Compare:

• a tua morada = your address
• o teu livro = your book
• a minha casa = my house

English does not use an article here, but Portuguese often does.

Leaving out the article is sometimes possible in certain contexts, but in European Portuguese a tua morada is the standard, natural choice.

In European Portuguese, morada commonly means a postal or home address.

So in this sentence, morada is the normal word for address.

A useful comparison:

• morada = address, especially a physical/postal one
• endereço = address too, but often used more broadly, and can also mean things like a web address or email address depending on context

A learner should especially remember this difference:

• In Portugal, morada is very common for a postal address.
• In Brazil, endereço is much more common for this meaning.

So this sentence sounds very European Portuguese.

No is a contraction of:

• em + o = no

Literally, em often means in, on, or at, depending on context.

So:

• no envelope = on the envelope / in the envelope, depending on the situation

In this sentence, because you are writing an address, English uses on the envelope, but Portuguese naturally says no envelope.

So do not translate em too literally every time. Its exact English equivalent depends on context.

Because Portuguese does not usually use sobre in this situation.

For writing something on the surface of an object like an envelope, em is the normal choice:

• Escreve a tua morada no envelope.

Using sobre o envelope would sound unnatural here, because sobre usually means about or on top of/over, not the normal way to say something is written on a surface in this context.

So even though English says on the envelope, Portuguese prefers no envelope.

Por favor means please.

In Portuguese, like in English, it can appear in different positions:

• Escreve a tua morada no envelope, por favor.
• Por favor, escreve a tua morada no envelope.

Both are correct.

Putting por favor at the end is very common and sounds natural. It softens the command and makes it polite.

Because it is a command.

In Portuguese, commands often begin with the verb:

• Escreve... = Write...
• Abre... = Open...
• Espera... = Wait...

That is the normal word order for imperatives.

If this were not a command, you would expect something different, for example:

• Tu escreves a tua morada no envelope. = You write your address on the envelope.

So the verb-first order helps show that this is an instruction.

A formal version would usually be:

• Escreva a sua morada no envelope, por favor.

Changes:

• escreve → escreva
• tua → sua

This is the version you would use with someone you want to address more politely or formally.

So:

• Escreve a tua morada... = informal, tu
• Escreva a sua morada... = formal, você

Usually it refers to a physical/postal address, not just any kind of address in the abstract.

Depending on context, it can be:

• a home address
• a mailing address
• an official address

It is not usually the first word you would use for things like:

• a website address
• an email address

For those, endereço is often more likely.

So in this sentence, the learner should understand morada as a normal postal address.

Yes, but that would normally change the level of formality.

Compare:

• a tua morada = your address when speaking informally to tu
• a sua morada = your address when speaking formally to você

So in this sentence, tua is not random: it matches the informal command escreve.

Mixing them would usually sound wrong:

• Escreve a sua morada... ← mixed informal verb + formal possessive
• Escreva a tua morada... ← mixed formal verb + informal possessive

Learners should usually keep them matched:

• Escreve a tua morada...
• Escreva a sua morada...