Which sentence is correct as below?

Who can join the lunch with us?

Who wants to join the lunch with us?

Both sentences are correct but they have slightly different meanings.

“Who can can join the lunch with us” could have many implications -

1/ who is permitted to attend the lunch - for example, if it is a lunch your friend organised, this sentence is like asking your friend who you can invite to join for lunch

2/ who is available to join lunch - for example, you asked your friends this question then the sentence is checking who has free time to come for lunch

If you want to see who is available for lunch, grammatically speaking, it is better to say “Who can join us for lunch?” instead of “Who can join the lunch with us?” because the meaning is clearer and it is clearly an invite, whereas in the original version the topic is more focused on Lunch as a subject and seeking permission.

cheers

Kate

Which sentence is correct as below?

Who can join the lunch with us?

Who wants to join the lunch with us?

Would you like to join us for lunch? -- Polite invitation.

Would you like to meet us for lunch? -- Polite invitation.

Please join us for lunch. -- Polite invitation.

Would you like to get lunch? -- Casual invitation.

Can you join us for lunch? -- This is more like a request.

Please join us for lunch. -- Request or polite demand.

Who can join us for lunch? -- You are asking who is able to go. This is less of an invitation and more just seeing who is able to.