Formal:
* 欢迎 (huānyíng): This is the most common and formal way to say "Welcome". It's used in a wide range of situations, from greeting guests to welcoming new employees.
Informal:
* 欢迎光临 (huānyíng guānglín): This literally means "Welcome your arrival" and is often used in businesses like restaurants and shops to greet customers.
* 欢迎回来 (huānyíng huílai): This means "Welcome back" and is used to welcome someone who has returned after being away.
Other options:
* 你好 (nǐ hǎo): This means "Hello" but can also be used as a way to say "Welcome" in informal settings.
* 请进 (qǐng jìn): This means "Please come in" and is often used when inviting someone into a room or building.
Which one to use:
* Use 欢迎 (huānyíng) for most situations.
* Use 欢迎光临 (huānyíng guānglín) in businesses.
* Use 欢迎回来 (huānyíng huílai) when welcoming someone back.
* Use 你好 (nǐ hǎo) or 请进 (qǐng jìn) in informal settings.
You can also use a combination of these phrases, such as "欢迎光临，请进 (huānyíng guānglín, qǐng jìn)" which means "Welcome, please come in".
Ultimately, the best way to say "Welcome" in Chinese depends on the specific situation and your relationship with the person you are greeting.