Your workplace might have a specific letter they require. I just filled mine out today!
@Bhumika thank you đź©·
The government of BC has a bunch of templates. One of them is to notify your employer. I'm sure these are generic templates and can be used by people of any province. Check the list out. https://www2.gov.bc.ca/gov/content/careers-myhr/all-employees/leave-time-off/maternity-parental-pre-placement-adoption/maternity#forms
I asked my midwife to write mine for me and sign it.