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

Yes

The word "assinatura" is identical in meaning, spelling, and grammar in both Brazilian and European Portuguese. It refers to both a handwritten signature on a document and a subscription to a service (like a magazine, newspaper, or streaming platform). The only difference is pronunciation:

• Brazilian Portuguese (BP): The vowels are more "open" and clearly articulated. The unstressed vowels are pronounced distinctly.
• European Portuguese (EP): The vowels in unstressed syllables are "reduced" or "closed." The "a" sounds in the middle of the word often sound like a very short, neutral "uh" (a schwa), and the rhythm is more consonant-heavy and clipped.

Brazilian Portuguese Examples

1. Eu preciso da sua assinatura neste contrato. (I need your signature on this contract.)
2. Minha assinatura da Netflix acabou ontem. (My Netflix subscription ended yesterday.)
3. Você já renovou sua assinatura da revista? (Have you renewed your magazine subscription yet?)
4. Não esqueça de colocar sua assinatura no final do e-mail. (Don't forget to put your signature at the end of the email.)
5. A assinatura digital é muito mais prática. (Digital signature is much more practical.)

European Portuguese Examples

1. Preciso da sua assinatura neste contrato. (I need your signature on this contract.)
2. A minha assinatura da Netflix terminou ontem. (My Netflix subscription ended yesterday.)
3. Já renovaste a tua assinatura da revista? (Have you renewed your magazine subscription?)
4. Não te esqueças de colocar a tua assinatura no fim do e-mail. (Don't forget to put your signature at the end of the email.)
5. A assinatura digital é muito mais prática. (The digital signature is much more practical.)