‎Is this sentence grammatically correct?
“Please be so kind to share information about vacant places as soon as they will be available”

Question

​‎Is this sentence grammatically correct?
“Please be so kind to share information about vacant places as soon as they will be available”

Answer

Please be so kind as to share information about vacancies as soon as they become available.

Answer

Please be so kind as to share information about any vacancies as soon as it is available.

'It' refers to 'information' since 'information' is both singular and plural. 
Or you could say:

Please be so kind as to share information about any vacancies that become available.

Does this help?

Answer

you could also say ' please could you inform me if there are any vacant spaces'