You can start deworming at 1 year and repeat every 6 months. There are different types of deworming drugs and they can be bought without a doctors prescription.
Albendazole is a good choice. The dosage should be given to you by the pharmacist based on your child's age (200 mg /400 mg; 200 mg for children below 2 years and 400 mg for those above 2 years).