The job specification (or ‘person requirements’) of a vacancy must not exclude disabled people from applying for a job.
However, some jobs may have an essential requirement that cannot be met with a reasonable adjustment.
A vacancy for a van driver says the person must be able to drive. This might exclude some disabled people, but it is an essential part of the job.
A company advertises a job with occasional travel necessary. The person could go by train so the company should not say that the person needs a driving licence.
If you reject a disabled candidate, it must be based on their performance at interview rather than having to make reasonable adjustments.