Formal:
* Olá, prazer em conhecê-lo(a). (This is the most common and polite way to say it. Use "conhecê-lo" for a man and "conhecê-la" for a woman.)
* Bom dia/Boa tarde/Boa noite, é um prazer conhecê-lo(a). (This adds a greeting to the beginning, depending on the time of day.)
Informal:
* Oi, prazer em te conhecer. (This is a more casual greeting.)
* E aí, tudo bem? Prazer em te conhecer. (This is very casual and is more like "Hey, what's up? Nice to meet you.")
Important Notes:
* "Prazer em conhecer" means "pleasure to meet you." It's a common phrase in Portuguese.
* "Te" is used in informal settings, while "lo" or "la" is used in formal settings.
* Always use "lo" for men and "la" for women.
You can choose the best option depending on the context and the person you're talking to.