Hypothesis:

A = European country

B = US company

X = National resident from A

X works while being physically in A for B.

After job done, X (as individual) issues an invoice addressed from his Thai residence to B and then gets paid directly to his Thai bank account via wire transfer.

Regarding Thailand and legally, does X have to declare this income? Does X need a work permit as well?

You'd have to declare your income in A for tax in A.

In Thailand you have to declare remittances into Thailand if the money was earned in the year in which it is remitted, so you'd have to declare it in Thailand and pay tax.

You wouldn't need a Thai work permit.

You'd have to declare your income in A for tax in A.

In Thailand you have to declare remittances into Thailand if the money was earned in the year in which it is remitted, so you'd have to declare it in Thailand and pay tax.

You wouldn't need a Thai work permit.

Assuming of course "X" is in Thailand for more than 180 days, if less...one could argue person concerned is not legally resident for tax purposes, the problem I see with this is how the OP would be able to issue a "legal" invoice from Thailand if one is not operating a Thai business

You'd have to declare your income in A for tax in A.

In Thailand you have to declare remittances into Thailand if the money was earned in the year in which it is remitted, so you'd have to declare it in Thailand and pay tax.

You wouldn't need a Thai work permit.

Assuming of course "X" is in Thailand for more than 180 days, if less...one could argue person concerned is not legally resident for tax purposes, the problem I see with this is how the OP would be able to issue a "legal" invoice from Thailand if one is not operating a Thai business

Thank you both for your answers.

Regarding what is a "legal" invoice in Thailand, I assume an individual is able to invoice legally with his name and address however does he have to be a Thai resident or even Thai citizen?

You'd have to declare your income in A for tax in A.

In Thailand you have to declare remittances into Thailand if the money was earned in the year in which it is remitted, so you'd have to declare it in Thailand and pay tax.

You wouldn't need a Thai work permit.

Assuming of course "X" is in Thailand for more than 180 days, if less...one could argue person concerned is not legally resident for tax purposes, the problem I see with this is how the OP would be able to issue a "legal" invoice from Thailand if one is not operating a Thai business

Thank you both for your answers.

Regarding what is a "legal" invoice in Thailand, I assume an individual is able to invoice legally with his name and address however does he have to be a Thai resident or even Thai citizen?

If you are issuing invoices from Thailand for services, it could suggest 1. you are working from Thailand as it suggests you are working from a "Thai entity" although there is none in place.

2. A lot of overseas companies will not accept "hand written" invoices, as their accounts departments will not accept them, as the local tax regime will not accept them as they are not from a legally registered company....ie the invoices may not be legit and this certainly would be the perception with invoices being issued from Thailand.

The point I am trying to get at is be very careful what you are doing if you are "pulling a funny" to circumnativate tax laws in countries A B & Thailand because you are establishing a paper trail.

If you are issuing invoices from Thailand for services, it could suggest 1. you are working from Thailand as it suggests you are working from a "Thai entity" although there is none in place.

Actually my point is to know if someone can issue an invoice from Thailand as an individual without working nor invoicing while being there (althought got an address/residence in Thailand)... or it should necessarily be from a (Thai) company? ... also in order to invoice from Thailand that individual must reside/work in the said country?

2. A lot of overseas companies will not accept "hand written" invoices, as their accounts departments will not accept them, as the local tax regime will not accept them as they are not from a legally registered company....ie the invoices may not be legit and this certainly would be the perception with invoices being issued from Thailand.

The point I am trying to get at is be very careful what you are doing if you are "pulling a funny" to circumnativate tax laws in countries A B & Thailand because you are establishing a paper trail.

A friend of mine issues "computer made" invoices at his name/home address (not a company) from Europe to a US company. Apparently, the US company does not mind. Obviously, he has to declare this income in the country from where invoices have been sent.