Is the word preencho the same in Brazilian and European Portuguese?

Yes

The word preencho is identical in both Brazilian and Continental Portuguese regarding its spelling, meaning, and grammatical function (it is the first-person singular present indicative of the verb preencher). The only difference lies in pronunciation. In Brazil, the vowels are generally more open and clearly articulated. In Portugal, unstressed vowels are much more subject to reduction; therefore, the "e" in "preencho" is often shortened or nearly silent, making the word sound more compressed and "clipped."

Brazilian Portuguese

1. Eu preencho o formulário todos os dias. (I fill out the form every day.)
2. Eu preencho todos os espaços em branco. (I fill in all the blanks.)
3. Eu preencho o tanque de gasolina. (I fill the gas tank.)
4. Eu preencho meu tempo lendo livros. (I fill my time reading books.)
5. Eu preencho a vaga de emprego. (I fill the job vacancy.)

Continental Portuguese

1. Eu preencho o formulário todos os dias. (I fill out the form every day.)
2. Eu preencho todos os espaços em branco. (I fill in all the blanks.)
3. Eu preencho o depósito de combustível. (I fill the fuel tank.)
4. Eu preencho o meu tempo a ler livros. (I fill my time reading books.)
5. Eu preencho o lugar na equipa. (I fill the spot on the team.)