If you enter Brazil with a temporary visa, you generally become a Brazilian tax resident on the date you complete 184 days of presence, consecutive or non-consecutive, within a period of up to 12 months. Other circumstances may make you a tax resident earlier, including obtaining permanent residence or qualifying employment.
https://www.gov.br/receitafederal/pt-br/assuntos/meu-imposto-de-renda/preenchimento/dsdp/nao-residente