Your precise trekking checklist depends on where exactly you're going and the need of the weather and other conditions of the trekking route. However, you can go with this basic and detailed Trekking Checklist and add or remove whatever suits or doesn't suit your location's needs. Here you go:
Trekking shoes, Backpack, Trekking pole, Three warm layers of clothes, Two trek pants, Two collared t-shirts, Thermals, Sunglasses, Suncap, Synthetic hand gloves, Balaclava or woolen scarves, Socks, Sports, and woolen clothes, Headlamp or LED torch, Poncho, Daypack 20 liters, Sunscreen, Moisturizer, Light towel, Lip balm, Toilet paper, Toothbrush, Toothpaste, Hand sanitizer, Ziplock bag, Lunch box, Coffee mug, Spoon, Two water bottles of 1 LTR each, Plastic bags to compartmentalize things and for wet clothes, Original and photocopy of Government photo ID card, Disclaimer form, Medical certificate, Mobile Phone, Phone charger, Power Bank, Air tickets, Train tickets, Slippers.
Medicines: Diamox for AMS, Dexamethasone, Nifedipine, Crocin for fever, Avomin for motion sickness, Avil for Allergies, Combiflam, Norflox for Diarrhoea, Digene for acidity, Omez/ Rantadine for Antacid, Crepe bandage, Gauze, Band-aid, Cotton, ORS, Betadine or antiseptic cream, Moov spray for a sprain, Knee cap, Antifungal powder.
As I said, you can add or remove things based on the need of your trekking location. Hope this answers your question.