Dear Shabana,
In most of the MNCs, appraisals are done on a half-yearly or yearly basis. In my company, it is being done on a yearly basis. In yearly appraisals, the performance of an employee is evaluated, and these are done by the year-end. However, in confirmation appraisals, although the performance is evaluated, it is more of a formality conducted at the time of confirmation. For example, if someone joins in March, their first appraisal will be done after their probation is over, which is the confirmation appraisal, typically after six months, in August. Subsequently, their appraisal will be conducted again in December (Yearly appraisal) along with the rest of the employees.
Regarding arrears, if the finalization of salary according to the appraisal is done in February, then you will receive the arrears from January added in February itself.