There are two types of leave policies followed by IT companies that I am aware of.
Type 1
The conventional style consists of 21 earned leaves (EL), 6 casual leaves (CL), and 6 sick leaves (SL). In some organizations, the 6 CL and 6 SL are combined to make 12 CL or 12 SL. By the year-end, the EL and SL are carried forward, and the CL lapses. You can accumulate a maximum of 42 EL, which can then be encashed. SL cannot be encashed. When taking an EL, any holidays or weekends falling in between are added to it; however, in the case of CL and SL, this does not apply. CL cannot be combined with any other type of leave. This policy includes 90 days of maternity leave and 3 days of paternity leave. Additionally, there are 10 declared holidays, and some organizations also offer 5 restricted holidays (RH).
Type 2
This policy is very straightforward, with no CL, SL, or EL, but rather 30 business days of holidays per year. This means you can take 30 working days off in a year, either all at once or in intervals. Holidays or weekends that fall in between are not included. At the year-end, 15 leaves lapse, and 15 are carried forward. This policy is simple to calculate, administer, and understand. Maternity and paternity leaves remain the same, as do the 10 declared holidays. This information may help you decide on the distribution of leaves. By the way, the total leaves applicable in your organization may be fewer if you choose to differentiate them. The number of leaves depends on the location and the minimum leaves specified under the shop act.
Hope this helps.