Sentence: For those, who does not have badge, ask me.

English as a Second Language English Vocabulary, Grammar and Idioms
1

Who = Singular or Plural?

Is this sentence correct:

“For those, who does not have badge, ask me.”

Best regards

2

You can use who to replace singular or Plural noun. It both Ok.
And:
For those, who do not have badge, ask me. is correct

3

‘Those who do not have badges may ask me’ will be more acceptable.
(‘who’ is plural here as it qualifies ‘those’)

4

Those who do not have badges may/should/can ask me.
Those who do not have a badge may/should/can ask me.

All are equally acceptable.

Suresh and Son, conversationally you could use your corrected form, though it is not standard grammar. However, it would be punctuated like this:
“For those who do not have a badge, ask me.”

5

Thanks to all, for your answers!

6

Any way, I mostly rely on the people who are Natives (English as their mother tongue).

7

That’s good, but not always so, especially when you take an examination, because those who evaluate your performance would usually follow what our universities like the CIEFL teach us. This may be slightly different from what we might see here. Information and knowledge gathered through discussions on this forum would certainly facilitate a comparison of theory with practice and an assessment of how fast and how far the English language has grown or is growing. Good luck, Suresh!